A rules question!

A) Not rules-related: the Cameron ball marker is intended to let you be fairly sloppy. The goal isn't to get the main line pointed straight at the right line, but simply to be within, what, 30 degrees of the line so you can use one of the lines to the side? So if you find yourself rotating it frequently, I suggest taking an extra second to get it lined up better to begin with so that you're within a reasonable angular region of acceptability.

B) I avoid all doubt and replace my ball if I ever need to adjust the line. Despite what I said in A, it's easier to line the ball up near to the main line than 20° away from it, so if I have the time, I replace my ball, adjust the marker, and pick up the marker.

This is not the clearest portion of the rules, though I'm sure a super-experienced rules person will know. For example, the player isn't penalized for accidentally moving his ball marker when marking the position of the ball or when repairing a ball mark:

Source: Rule 16-1c
The player may repair an old hole plug or damage to the putting green caused by the impact of a ball, whether or not the player's ball lies on the putting green. If a ball or ball-marker is accidentally moved in the process of the repair, the ball or ball-marker must be replaced. There is no penalty, provided the movement of the ball or ball-marker is directly attributable to the specific act of repairing an old hole plug or damage to the putting green caused by the impact of a ball. Otherwise, Rule 18 applies.

Source: Rule 20-1
If a ball or ball-marker is accidentally moved in the process of lifting the ball under a Rule or marking its position, the ball or ball-marker must be replaced. There is no penalty, provided the movement of the ball or ball-marker is directly attributable to the specific act of marking the position of or lifting the ball.

This decision is semi-relevant:

Source: Decision 20-1/6
Ball-Marker Moved Accidentally by Player in Process of Marking Position of Ball

Q. A player marked the position of his ball with a coin, lifted the ball and pressed down the coin with the sole of his putter. He walked to the edge of the green and then noticed that the coin had stuck to the sole of the putter. What is the ruling?

A. In this case, the movement of the ball-marker was directly attributable to the specific act of marking the position of the ball.

Accordingly, no penalty is incurred and the ball or the ball-marker must be replaced. If the spot where the ball or ball-marker lay is not known, it must be placed as near as possible to where it lay but not nearer the hole (Rule 20-3c).

The way I see it, if the Rules let you accidentally move your ball marker 30 feet because it's stuck to your putter, they're not going to have a problem if you're twisting it in place. They let you tap the ball marker down, too, and call that "the act of marking the ball."

Two more relevant rules. This one is a corollary to the last one I cited:

Source: Decision 20-1/5.5
Ball-Marker Moved Accidentally by Player

Q. A player marked the position of his ball on the putting green and lifted the ball. When it was the player's turn to play, he could not find his ball-marker. Subsequently, he found the ball-marker stuck to the sole of his shoe. He concluded that he had accidentally stepped on it while assisting his partner in lining up a putt. What is the ruling?

A. The player incurs a penalty stroke under Rule 20-1 which requires that the position of a ball be marked before it is lifted, and contemplates that the ball-marker will remain in position until the ball is replaced. The player must place the ball as near as possible to its original position but not nearer the hole — Rule 20-3c.

Under the last paragraph of Rule 20-1, a player is exempt from penalty if his ball-marker is accidentally moved in the process of lifting the ball or marking its position. In this case the ball-marker was not moved during such process.

So the difference seems to be whether adjusting the position of the ball marker is considered an act of "marking the ball." I think this Decision may be the best yet (emphasis mine):

Source: Decision 20-1/12
Ball-Marker Moved Accidentally By Player After Having Moved Loose Impediments

Q. A player marked the position of his ball on the putting green with a coin and lifted the ball. He then placed his finger on the coin, while he brushed aside some loose impediments so that he did not move the coin. On lifting his finger the coin initially stuck to his finger before falling to the ground and coming to rest in a different position. What is the ruling?

A. The act of placing the finger on the coin is considered to be an extension of the marking process (see Decision 20-1/6). Therefore, as the movement of the coin was directly attributable to the specific act of marking the position of the ball, the player incurs no penalty and the ball or ball-marker must be replaced (Rule 20-1).

So let's put it this way: I'd never call you on it if you just walk up to your ball marker and twist it. Under the rules, that seems to be no different than tapping down the ball marker or something like that. The Rules also allow you to mark to the side without first marking your ball, and the general guideline of the Rules has never been to catch someone in a silly technical violation where a ball marker might be a millimeter closer because you twist it.

That all said, so as to avoid ANY perception of impropriety, I always put the ball down on the occasions when I twist the ball marker because then there's no doubt that I'm actively marking the position of the ball.

I'm going to have to disagree. See the bold part of Decision 20-1/12 in my post above. And the ball isn't in place in Decision 20-1/6, either, and that's a gross movement of the ball - not rotation-in-place.

The Rules are clear to delineate that if you drop your ball marker on the ball that's NOT "the act of marking the ball," and you get a penalty, and to delineate further that simply placing your finger on the ball marker continues "the act of marking the ball" in this Decision.

And I would argue, currently, that in equity there's no penalty, because there are clear situations in which the ball marker - without a ball present - is moved accidentally and the player is not given a penalty.

Tapping down is movement just as rotation is movement, yet the rules specify that you can move a ball marker 20 yards accidentally by moving by tapping down and replace it with no penalty. Furthermore, your rule penalizes the act of touching the ball in an unlawful manner:

Source: Decision 18-2a/33 Rotating Ball on Putting Green Without Marking Position Q. A player rotates his ball on the putting green to line up the trademark with the hole. He did not lift the ball, mark its position or change its position. Is there a penalty? A. Yes, one stroke for touching the ball other than as provided for in the Rules — Rule 18-2a. Under Rules 16-1b and 20-1, a ball on the putting green may be lifted (or touched and rotated) after its position has been marked. If the player had marked the position of the ball before rotating it, there would have been no penalty.

It does not penalize for "movement." The rules regarding when you can touch your ball are a lot stricter than the rules for when you can touch your ball marker (for example, when brushing loose impediments away as cited above AND when moving your marker to the side), and I believe they allow this type of rotation as well. Plus, movement is defined as:

Source: Definitions Move or Moved A ball is deemed to have "moved" if it leaves its position and comes to rest in any other place.

That's not really the case with the ball marker being twisted "in place." I've also cannot recall a Decision or Rule that states that the marker represents the ball, and a search for that came up empty. All of that said, I again point out that I always put the ball down again in the rare cases when I do this myself. I'll follow up with some rules people I know to get their take on it.

You don't seem to have read Decision 20-1/12. In that case touching the marker is deemed to be an extension of the act of marking the ball.

Have you read the decision regarding dropping your coin on the ball? You're penalized there too. The bottom-of-the-shoe thing was also accidental, yet the player is penalized. So no, I don't see the line between "accidental" and "non-accidental." Sometimes accidents are punished here, sometimes they aren't. I also don't see the line between "the act of marking" or not, and 20-1/12 makes the case there. Brushing loose impediments isn't "marking" but it's considered an extension of the act by that Decision because the player was taking steps to maintain the proper marking while also removing loose impediments as he is allowed.

I don't buy that it's the exception, and the "rotating the ball" penalizes the player not for moving the ball, but just for touching it. It doesn't even stipulate that the ball "moved."

When a ball "moved" is fairly clearly defined. Rotating in place isn't movement, and the player isn't penalized for moving the ball - just for touching it.

Except in Decision 20-1/12. Or 20-1/6.

Rotating the ball marker isn't a careless accident like stepping on it. It's much more like a purposeful act like brushing away loose impediments. I'm also not suggesting that the player lie, but what about a situation in which the player rotates the ball marker and brushes away a bug or a bit of sand on his line? That's right up 20-1/12's alley. Perhaps I'm wrong, but I don't think I am. That said, I've laid out my case and find no other relevant rules or decisions that support either side, and I'm confident that what I do in my own golf game is fully legal, so I'm going to wait until the rules officials I've contacted can get back to me.

In the situation you outlined, you must use a putter or some other object to mark the position temporarily.

This is the part Jay-Bird got right - you're allowed to change the position of a mark. The mark is not the position of the ball - that point is on the green and not where your mark is. You can put your mark to the side of the ball (though it's not recommended).

Now, the Rules of Golf state that you are not allowed to use a discolored piece of grass or something as a "mark," but that involves no physical object. If you were to stare at the spot where your ball goes I'm not sure if you could move a marker relative to that. However , if there's a loose impediment near that spot, that can be used to mark the location of the ball.

Source: Decision 20-1/19 Placing Object Marking Position of Ball Other Than Behind Ball Q. When marking the position of a ball, must the ball-marker be placed behind the ball, or may it also be placed to the side of or in front of the ball? A. There is no restriction. However, if a player positions his ball-marker in front of the ball on the putting green and in the process does something to the green which might influence the movement of the ball when played, e.g., presses down a raised tuft of grass, he is in breach of Rule 1-2. Placing a ball-marker in front of the ball is not recommended but it is not a breach of Rule 16-1a because this Rule permits touching the line of putt in lifting a ball, and marking the position of the ball is part of the lifting process.

Here's the blemish decision:

Source: Decision 20-1/16 Method Used to Mark Position of Ball Q. The Note to Rule 20-1 provides that "the position of a ball to be lifted should be marked by placing a ball-marker, a small coin or other similar object immediately behind the ball." Is a player penalized if he uses an object that is not similar to a ball-marker or small coin to mark the position of his ball? A. No. The provision in the Note to Rule 20-1 is a recommendation of best practice, but there is no penalty for failing to act in accordance with the Note. Examples of methods of marking the position of a ball that are not recommended, but are permissible, are as follows: • placing the toe of a club at the side of, or behind, the ball; • using a tee; • using a loose impediment; • scratching a line, provided the putting green is not tested (Rule 16-1d) and a line for putting is not indicated (Rule 8-2b). As this practice may cause damage to the putting green, it is discouraged. However, under Rule 20-1 it is necessary to physically mark the position of the ball. Reference to an existing mark on the ground does not constitute marking the position of a ball. For example, it is not permissible to mark the position with reference to a blemish on the putting green. When moving a ball or ball-marker to the side to prevent it from interfering with another player's stance or stroke, the player may measure from the side of the ball or ball-marker. In order to accurately replace the ball on the spot from which it was lifted, the steps used to move the ball or ball-marker to the side should be reversed. (Revised)

Again, there's a difference between moving the marker and moving the ball. I think it's reasonable to assume that a player can move a marker slightly while retaining the original location of the ball. This is particularly true if you put your finger down or otherwise mark the position of the ball while the original marker is moving. That could include your putter or any small loose impediment on the green (a grain of sand, a tiny rock, a dead bug, a clipped blade of grass), and then you're perfectly well allowed to move the marker.

No, the Rules don't care what ball marker you use (see above). You can use a putter as your temporary stand-in ball marker. You can use a rock. You can use a can of beer. A tee. A divot repair tool. Your hat... they recommend a small, flat, round object like a coin, but you can use whatever you like. I saw a guy use a flower he'd picked one time (to prove the point that it was legal). Also, you don't have to rotate it about the position of the ball. You could rotate the Cameron marker "in place" if you wanted.

Another reason I believe this is in equity: nobody can put a ball back EXACTLY where it was even if they don't "rotate" their ball marker. I believe that you can rotate a ball marker and maintain the same margin for error where you place the ball as the normal people who mark their ball with a coin. Also, you'd have to be a pretty big douche to call someone on rotating their ball mark, too. They've not really gained an advantage they couldn't otherwise obtain (by lining up more carefully the first time, or by re-aligning by placing their ball). They're not closer to the hole and it's like penalizing someone solely for being lazy and/or trying to be a little faster.

I know what you meant and I don't need a picture. I still also think that's mostly irrelevant - the rules don't care what you've marked your ball with. The rules do, however, give the player several instances in which the marker can be moved without penalty (and under which you are penalized).

The rules also don't make a distinction between "rotating in place." I get that you're suggesting that rotating a round object won't change the mark the first time. It's possible to rotate a Cameron ball tool without moving it to a new "place." Additionally, you could argue that since the Cameron marker contains a cutout, it'd be very easy to move the object along that arc and maintain the original ball position - which is what matters here. That seems to me to be no less sloppy or have no larger margin for error than a round marker - was the marker placed exactly in line with the hole or was it at a slight angle? Get that wrong and the ball is technically moved - at least as much as the ball would move by rotating the Cameron marker in place and using the new center of that arc to place the ball.