All the zoos that I've been to make it impossible to stick you hands into the enclosure of a dangerous animal, using either glass, barriers, fine mesh or a combination of all three. The fact that she was able to put her hand into the enclosure is worrying as it would imply that a child might be able to do the same.
Because she's an adult of supposed sound mind and should know better I hope she doesn't get a penny from the zoo in damages.