Fortunately, I never had to deal with kids in my career. I could just envision how I'd respond when they rub their jelly covered hands on the front of my f1.2 lens...
I think I'd use a combination of 'Dirty Harry' and 'The Godfather' to control the parents..."This is a 44 magnum...either you or your brains will be outside the door in 5 seconds..."