Is This Cheating?

[GlennG]

While we were playing Munchkin the other night one of the players started messing with me from the first monster I drew until about the mid point of the game, he was out of cards.

He kicked in the door and drew a monster that he could beat, he asked if anyone was going to do anything to stop him, no one replied. So I said, "if you give me the monster's treasure I won't stop you from winning this fight." He agreed.

Two of the guys playing freaked out. They said that I was cheating by doing that. I said its all part of playing the game but decided not to go through with the deal because they were so bent out of shape about it.

Who was right? Can you bribe someone like that?