The first time (and so far only time) I performed at school, I was doing the biddle trick, and they took the cards from me in the middle of the trick and said "I can do something better than that", and proceded to do the 21 card trick. He did not even let me get half way through the trick, so I know there was no way he knew what I was doing at that point. All he had done was pick a card.
I hope this year brings better luck with performing outside of magic club.
Hah, that's funny, well obviously not at the time. I hope you explained to people that your trick was more interesting and proceeded to outshow the guy doing 21 card trick!