Be prepared! I used to volunteer for an non-profit that did rehab & educational programs for native raptors. Having a compound full of cages, we also ended up taking in a variety of other critter (eventually including 4 green Ig's, that have since become my own personal responsibility & reward). At any rate, occasionally we'd bring one of the big Ig's to close the education program (after all, you can pet an Ig easier than most Red Tail Hawks) and I'll never forget the night we went to a huge Cub Scout jamboree they held at the old Dallas Cowboys training camp. There were SOOO many LITTLE boys there. They all sat somewhat patiently (figgitingly actually) through the raptor program and as the speaker was closing I got Shirley out of the carrier and began approaching the front of the low stage on which we were perched. Let me tell you what. . . when the speaker said "you can come up and pet the Iguana if you'd like", those little guys rushed the stage like a bunch of teenagers at a Beetles concert. Yikes!!!
Hence my advice "be prepared".
Rebecca (and the zoo)