catman--
Education is a big part of our hobby, and providing children an opportunity to interact with reptiles is an effective way to advocate understanding of beautiful animals.
The chin bite is most unfortunate. Not only was snake day cancelled, but negative attitude was focused on the hobby. In addition, you've opened yourself up to liability. The bite was not the result of the child holding the snake up to her face. The bite was the result of you not having the snake under control, and letting her put it up to her face when it bit her. Children don't listen, especially when, as you admit, they are excited. It's the adult's responsibility to expect that, and to ensure that a child interacts with the animal in a safe context. Better hope that the child doesn't develop a zit and her parents' blame it on the bite.
For what it's worth: when I work with kids and a snake in the same space, I hold the snake's head securely. Then I have them wash their hands before putting up two fingers to stroke the snake from the neck towards the tail as I support the body with the other hand. If I have my Bci (6 ft.), they may gently stroke her with one hand, one person at a time. If I am taking multiple animals, I either take them out one at a time, or ask trusted herp friends to be there. Very rarely, I may allow a child to hold a snake's body, while I control the head. So far (knock on wood, my head, thank the goddesses), there have been no unfortunate incidents. After touching, they must once again wash their hands with soap and water.
In places such as school settings, children should not simply be handed a snake to hold. Too many variables of what can happen, and not enough controls to prevent it. I hope that you will continue educating kids about snakes. Just think through some protocols that will keep both kids and snakes safe, and you out of court.
rgds,
althea