I just thought aboutt this little incident that happen to me at an IBC qualifier. It was the 3rd game and I was playing against a land destruction deck ( R/G/W ) I as down to 10 life and my opponent starts to tapp all his land and say he's Urza's Raging me for 10. I look over his permenants and realize that he only has 9 source of mana and 2 familiars. 1 shy of killing me. I pointed this out to him and the only thing he said was "Great now you know my hand " I proceed to play and won the game with in a few turns. My question is he tapped his lands for 9 mana into his pool I know he should have burned for 9 and he didn't ask me if its ok to take the mana back. Should I have pointed out that he should have burned for 9 or was it right to let it go ?