Often, when I get the "do a trick!" command, I reply with the same tone and enthusiasm that they used with, "give me money!"
Basically, it's the same principle as the "make me a hamburger" suggestion given earlier in this string. Or, I tell them I get $125 an hour to do tricks, the minimum is two hours and if they - now the customer - want just one trick, it will still cost them the minimum fee of $250.
So far, no one has decided that a single impromptu trick is worth $250; but I'm hopeful.
...And you can make up whatever amount per hour you want here or use a "per night" total. You get the idea.
I do see what people are saying. If they ran into Pavarotti, they would never even think of saying.." Sing an aria." I am pretty sure if they ran into David Coppperfield at some restaurant , after gushing and fawning, and getting his autograph they would say... " Do a trick!"
What I wonder about is.... would David Copperfield do one? I know he won't pull out Boxes or a Buzzsaw, but would he do the Rubberband trick? or Vanishing hanky?