same thing actually happened to me before, i cant remember exactly but i threw down my cards thinking i had no chance and hit runner runner straight. however the cards were mucked, you can say whatever you like, but the second the cards hit the muck or anything close in realtiy, its a dead hand.

in a home game though, if i knew it was an honest mistake and i was the "winner" with the inferior hand ,i would probably offer to split the pot, so all in all it was probably the right thing to do.

in my case it was a home game but did not know the guy who had beat me, so he refused to split, so although i think it was moraly the wrong thing, he was 100% right technically. i could never myself though take the whole pot if i knew i was going to lose and it was an honest type mistake.