If you brought peanuts, or peanut butter in, you just had to make sure you washed your hands really well after eating so as to leave no peanut residue anywhere. Simple.
It is ridiculous to segregate the peanut/peanut butter eaters...but we simply cannot segregate the one child..what about her self esteem?
WHOA! Let's not jump to conclusions about segregation, isolation, etc. The allergic child does not have to eat alone, just monitor those around him. In the same way, who said a ham and cheese eater can't eat with his friends in the peanut gallery?