lol yeah just like streetmagicrocks said,.... tell them to do it, give them a quarter and tell them to bite it out! They wont and then tell other members of the audience something. The person will shut up and feel silly soon after trust me...
A very bad way to go about it. A half way funny person Could make you look like a moron if you gave him this chance. Its also a bed idea because thats not going to make people want to watch. This makes it become a "hey look what i can do but you cant" game. Thats not what you should be going for.
The best way about it is going on yourslef. I love to do that. "Hey that sucks". "I know, im just a jesus wannabe who cant tun water into wine. Im sure you have that down though. Why dont you go look for your flask" Any jokingly polite way to ask them to leave is the way too go.
no, that is actually in my opinion coming off as weak. IT's obvious that they cannot do the things that u are performing, so that's evident. If u back off and let them say that it was easy and what not, you come off as weak. When u have them try to bite the quarter, it makes them seem stupid, and they won't quetion your effects ne more, trust me it works