Have you seen a couple of the trouble shots that Tiger hit. From the rough under a tree with a full 4 iron between to rows of spectators. I am sorry to say that unless the Marshalls move the crowds away to a safe distance Tiger may someday actually KILL a spectator. It is scary to watch.
First of all, the "marshalls" at PGA tour evnts are typically local senior citizens who know nothing about high level golf.
Second, it is really the player's responsibility to clear any and all spectators out of his line of play.