Ya, I would not recommend the Hummingbird Card in a school setting. Not only would the lighting be difficult, but it would be risky to carry the mechanism on your person for the entire day. Add to that the fact that most kids at school will try to mess you up in some way or another, or at least figure out what it is you're doing to make it work, and you've got yourself a contender for "Worst Trick to Perform at School in a Walk-Around or Strolling Magic Setting
". ...I wouldn't recommend the Levitating Woman illusion, either
. As for other tricks, I perform Ambitious Card, Two Card Monte, Card Warp, and Synergy all the time at school, to great success. I tend to stay away from gimmicked tricks at school, partly because I don't want to carry gimmicks all over my body, but also because I feel alot more confident knowing that my cards can be grabbed at (almost) any time during a trick, and not expose anything. I'm pretty sure that if someone's calling out the secret to a trick you're performing, you should try something other than the 21 Card Trick
. I would stick to tricks like the ones I have mentioned above, and you shouldn't have these problems anymore. Peace!