Make the secret a lot more trouble than the trick seems
worth. You will be fooled by a trick if it involves more
time, money and practice than you (or any other sane
onlooker) would be willing to invest. My partner, Penn,
and I once produced 500 live cockroaches from a top hat on
the desk of talk-show host David Letterman. To prepare
this took weeks. We hired an entomologist who provided
slow-moving, camera-friendly cockroaches (the kind from
under your stove don’t hang around for close-ups) and
taught us to pick the bugs up without screaming like
preadolescent girls. Then we built a secret compartment
out of foam-core (one of the few materials cockroaches
can’t cling to) and worked out a devious routine for
sneaking the compartment into the hat. More trouble than
the trick was worth? To you, probably. But not to
magicians.
Edit: That trick is 19 minutes and 50 seconds into this video.
His partner Teller says the same thing here:
Edit: That trick is 19 minutes and 50 seconds into this video.