[MDPokerAA]

It's not about disagreeing, it's about rules and commonly enforced practice. I've seen this happen many times playing Hold Em in Atlantic City... if the situation had happened exactly as AJ described, player A would have been awarded the pot provided at least one player or the dealer could verify his hand. Most floormen will ask if anyone saw his hand, and ask the dealer to confirm a player's hand, and then reward the pot to the winning hand. Cards being dead once they hit the muck, no questions asked, is a popular myth which is not always true. In fact, most of the time, it's specious.

In a home game, yes, usually either cards speak or cards die once they hit the muck. But I think AJ go all in is asking the question in the first place because he wants to get a different viewpoint. Either way, I agree that player A made a mistake and doesn't deserve the pot in theory, but in casinos and many home games, he is entitled to the pot because player B (the KK's) made the mistake of showing his hand.