Ken, you wouldn't believe what I saw. Totally common to see parents actually lifting kids up so they could stick their hands in coral lagoon (the "calm" tank that XTM posted above) so they could try and touch the fish. I amused myself by waiting until they went fingers wet and then I would call out over the crowd in one of those polite but firm... "Oh please don't do that, some of those fish BITE!
It was hilarious how fast they reeled those kids back in.
Brett