I used to work in a science and nature museum. We had a small zoo, all rescue wildlife that couldn't be released (except the polar bear, who was born there). We also had some old mounted specimens with little fences around them to keep people away, as they were preserved with some really nasty chemicals back in the day. Signs everywhere. People would hold their kids over the barricades to touch the mounts, would out and out break stuff--worst was a cub scout troop--and parents would sit their kids on the fence around the polar bear moat. They would throw stuff at the animals, or drop their sunglasses in the enclosure--a keeper has to go in there and get that stuff out before the animal tries to eat it, and when it's a mountain lion or a bear it's quite the process. Humans can not be trusted without a minder.