by bmat » Jun 16th, '11, 17:53
Perform the effect as laid out in the instructions! Too many times I've seen dealer demo's where the dealer pulls out a set of sponge balls, or cups and balls and then performs incredible feats (that are not in the instructions) then the customer goes home, reads the instructions and feel ripped off (because in a sense they were). The new person doesn't yet have the tools to re-create what the dealer did, so the dealer in effect showed one thing and sold another, bait and switch.
By all means you can do the fancy stuff. But make sure the customer knows that what you are now doing is not covered in the instructions, that you are just showing what will eventually become possible once they have much more experience.