Really? That bothers you? I could see if people are doing it while you are trying to putt, but I've seen this done 1000 times, probably done it myself 500 of those times, and have yet to ever see it leave a mark.
(For the record, I don't really do it anymore. If we're not in the dead center of a large green, I'll just drop it on the fringe. If we're on the green, I'll grab it by the end of the flag, "drop it" such that it's a foot off the ground, and then let go.)
Nothing really bothers me all that mcuh during golf (except countless things that my dad does, but that is a topic for a whole "nother" thread. Right @boil3rmak3r ??)
But last week my F-I-L and I got paired up with this really friendly gentleman for a round and he was one of those guys that had trouble keeping track of his ball. Either he forgot to watch it as it flew, or had bad depth perception, or whatever. On the first hole, after slicing two drives into the cactus (one of which hit a rock and bounded back into the fairway) he drove over to my ball (50 yards past where either of his balls could have possibly ended up) and checked to see if it was his.
That was no big deal, but what was kind of grating was the fact that instead of just looking at it, he, without hesitation, reached down and picked it up, then saw that it wasn't his, and dropped it back down.
On another hole, I was pitching from just off the green and lay my other wedge and my putter on the green near the edge of the green, and after he marked his ball while it was my turn, I saw him walk over to my clubs and he reached down with his putterhead and hooked the shaft of the wedge and moved it over off the putter a few inches. Some random dude just touched another guys clubs ... for no apparent reason!! Who does that???
Like I said, he was perfectly friendly and overall a decent partner (albeit, a horrendous golfer) but a few of the things he did were just plain odd.
Bottom line: If you want to play golf with me and you are not my wife ... please don't touch my balls or my shaft. Thank you very much.