I do not know all the facts, but per The Golf Channel, someone called in and said the saw McIlroy kick the sand in the bunker on 18 thus violating the rule against testing the sand. If this was correct, he would have signed for an incorrect score (the 7 on 18 not including the penalty stroke) and thus would have been DQed. Per The Golf Channel, the Masters officials finally ruled after reviewing the tape that there was no violation, and McIlroy stands at +1 after 36.
John,
I am very much interested in your opinion in this matter, and will grant much deference towards your opinion due to your greater experience in rules of golf situations.
However, I feel that one watching on TV can be too easily fooled or can too easily misinterpret what they have seen. I feel that it is wrong for a player to suffer going through the process of re-reviewing what occurred on the course (maybe many hours earlier) just because someone THINKS they saw on TV a rule violation.
At least if someone in the crowed sees something wrong, #1 their perception is not that much different than the perception as other players and officials have (that is not viewing the situation through TV which does distort things); and #2 they can alert a rules official immediately and the situations can be dealt with either before completion of that hole or at least within the next few holes, or at worst hopefully before the scorecard is signed.
Finally, there is the threat that this is taken out against a player that fan or spectator does not like. Perhaps a fan sees their most disliked player violate a rule accidently, but decides not to call it to the attention of rule officials until after he signs the scorecard hoping a DQ will occur. The other players and rules officials have a code of ethics (some official, some unwritten), and know that they have an obligation to call attention any rules violation they see as soon as possible. The fans do not have an obligation to this code of ethics. Unless an outside individual sees blatent/intentional cheating, or can warn the player right before a rule is violated, ALL rules situations should be left to those involved officially in that event.