We had an interesting situation happen in a no-limit texas holdem tournament.
On the river, Player A bet T1500. Player B raised all-in for T3500. Player A did not realize that Player B had raised and turned up his hand thinking he had been called. Player B then turned up his hand. We (the floor) were called over. Player A had the obvious winning hand, yet had not called. Player B was arguing that his hand should be dead, but we informed him, that although he has yet to call, he did not declare that he was folding and still had action. Player B used some expletetives to express his displeasure and Player A responded by saying, "Fine, you want to win the hand that way, I'm folding." and proceeded to throw his hand in the muck. We gave the Players a 1 round penalty for early exposure of cards, but then, the other players at the table complained that it was collusion, since it was obvious that he had the winning hand and should have taken Player B out of the tournament. Do you think A) that we should have made him call, or B) given him a stricter penalty for collusion if he did not? This was obvious to all of us that he was not colluding with this player, as we know that these two players do not, in fact, even like each other, yet he did allow another player to win with the second best hand and remain in the tournament.