The trailer is pretty misleading-watching a full performance, many lay people will be able to figure
it out. I’ve tried this about 10 times, and 3 or 4 they were able to guess the secret. Any magician
could get it immediately.
On top of that, it requires some semblance of crowd management.
Without giving it away, I’ve had it fail twice because the spectator had a different definition of
what a word was than I did, so you need to be very clear in what you’re saying.