Brian,
I'm a little confused on your explanation of that hand. I'm thinking that you got Players A and B mixed up (because Player B folded). I will also assume that the game was a flop game because that could make a difference in a ruling, also. If I understand the situation correctly, player C should not have been awarded any portion of that pot. Players must keep their cards on the table, not up in the air, or beyond the table edge. I don't agree with the ruling that the dealer was held responsible for what appears to be violations of poker etiquette by Player C.
The original post by Mike B is interesting because there are so many different scenarios that could have occured. If a player makes a bet and thinks that he has won the pot, only to discover that there is another player in the hand after he mucks his hand, then the hand is dead. If he knew that another player was in, why would he muck his hand? We would have to assume he truly did not see the other player, especially if he had a nut hand, for example. The perfect fix would have been for the dealer to recognize that the player was about to surrender his hand and stop him from mucking his hand and pushing it back to him and telling him that there is another player yet to act.
I like what Lewis said about the players holding onto their cards until the dealer pushes them the pot. That is a simple rule to follow for a player. Hold your cards until you see a hand better than yours, or until you get the pot pushed to you.