I think there is more to it than the above. First of all the rule above is rule 9: info as to strokes taken. So you must give correct info on strokes taken during a matchplay (including penalties).
Next there is the issue of seeing your ball go in the waterhazard.
Originally Posted by CraiginKSA
I tee off and I think I see my ball go into a hazard. The hazard is an area of grass, then water. My opponent sees a ball which is beyond the hazard and states that ball is hers. So I drop my ball, take a penalty and hit my third shot.
You thought the ball came to rest in the hazard and because a ball is not yours there is proof. This is not a correct way to establish virtual certainty, not even when that proved to be her ball. Desicion 26-1/1 is cristal clear:
Meaning of "Known or Virtually Certain"
When a ball has been struck towards a water hazard and cannot be found, a player may not assume that his ball is in the water hazard simply because there is a possibility that the ball may be in the water hazard. In order to proceed under Rule 26-1, it must be "known or virtually certain" that the ball is in the water hazard. In the absence of "knowledge or virtual certainty" that it lies in a water hazard, a ball that cannot be found must be considered lost somewhere other than in a water hazard and the player must proceed under Rule 27-1.
When a player's ball cannot be found, "knowledge" may be gained that his ball is in a water hazard in a number of ways. The player or his caddie or other members of his match or group may actually observe the ball disappear into the water hazard. Evidence provided by other reliable witnesses may also establish that the ball is in the water hazard. Such evidence could come from a referee, an observer, spectators or other outside agencies. It is important that all readily accessible information be considered because, for example, the mere fact that a ball has splashed in a water hazard would not always provide "knowledge" that the ball is in the water hazard, as there are instances when a ball may skip out of, and come to rest outside, the hazard.
In the absence of "knowledge" that the ball is in the water hazard, Rule 26-1 requires there to be "virtual certainty" that the player's ball is in the water hazard in order to proceed under this Rule. Unlike "knowledge," "virtual certainty" implies some small degree of doubt about the actual location of a ball that has not been found. However, "virtual certainty" also means that, although the ball has not been found, when all readily available information is considered, the conclusion that there is nowhere that the ball could be except in the water hazard would be justified.
In determining whether "virtual certainty" exists, some of the relevant factors in the area of the water hazard to be considered include topography, turf conditions, grass heights, visibility, weather conditions and the proximity of trees, bushes and abnormal ground conditions.
Now back to the question asked
Giving information is ok as long as you are not giving advise. Giving incorrect information is ok as long as you are not giving advise but......... see rule 33-7 and desicion 9-2/12
33-7. Disqualification Penalty; Committee Discretion
A penalty of disqualification may in exceptional individual cases be waived, modified or imposed if the Committee considers such action warranted.
Any penalty less than disqualification must not be waived or modified.
If a Committee considers that a player is guilty of a serious breach of etiquette, it may impose a penalty of disqualification under this Rule.
Conscious Failure to Correct Opponent's Misunderstanding of State of Match; What Constitutes Wrong Information
Q.In a match, B is 1 up on A playing the 14th hole. A and B take 6's at the 14th hole, but B, assuming A scored a 5, says: "We are now all square." A says nothing although he knows that both have scored a 6 and he is still 1 down.
At the end of the 17th hole, B, believing he is 2 down, concedes the match, although in fact he is only 1 down. Is A subject to penalty under Rule 9-2 for giving wrong information?
A.No. Rule 9-2 deals with giving wrong information as to the number of strokes taken at a hole and would include acquiescence by the player (whether oral or tacit) in a misstatement by his opponent of the number of strokes taken by the player. Wrong information does not include acquiescence by the player in a misstatement by his opponent of the result of a hole or the state of the match.
However, A's conscious failure to correct B's misunderstanding of the state of the match is so contrary to the spirit of the game that the Committee should disqualify A under Rule 33-7 and reinstate B.