Watching Yankees pitcher Andy Pettitte in this postseason, I am struck by how he repeatedly gets away with balk moves. The announcers haven't ignored this, they just say that if you do something consistently, the umpires will tolerate it.
The announcers are really shirking their duty to the viewers here. They should state unequivocally that the umpires are not doing their job with their non-enforcement of the balk rule. The rule states that it is a balk if "The pitcher, while touching his plate, makes any motion naturally associated with his pitch and fails to make such delivery." Pettitte repeatedly starts to go to the plate, then switches in midstream and throws to first. There are other rules which apply as well, and Pettitte is allowed by the umpires to violate them all without sanction.
Pettitte is no fun to watch, he is a lousy cheater, and the umpires should be disciplined for their tolerance of his cheating. It is said part of the reason for the tolerance is that he is a veteran. Well, if it is a balk when a rookie does it, then it should be a balk when a veteran does it.