Here's an interesting perspective by Bruce Weber on the Derek Jeter incident the other night, where he feigned being hit by a pitch that actually struck the knob of his bat. Weber says it's not the players who are supposed to keep game honest, it's the umpires:
I’d argue that a prime function of officials is to relieve players of the burden of honor. After all, on a bang-bang play at first base, when the runner is called safe but knows in his heart he was out, he does not feel compelled to correct the umpire’s misimpression.
Officials, not athletes, are the ones who make sure that the game is fair. One thing that means is that opponents have equal opportunity to influence them. This is why it is not only acceptable but entirely accepted that soccer players will careen to the ground after a slight jostle, hoping to induce a yellow card; that offensive and defensive linemen will point at each other after a whistle on the line of scrimmage, each accusing the other of moving first; that catchers habitually tug an outside pitch toward the plate in an effort to convince the ump that a ball is a strike, the baseball version of "Who are you going to believe? Me or your own lying eyes?"
Weber's entire piece is here. His book is "As They See 'Em: A Fan's Travels In The Land Of Umpires." I had a conversation with him when the book was published in May, 2009, which you can listen to here.