When I was in grade school I knew a kid who had a serious allergy to peanuts. We were all told of his condition and asked to be safe around him and he never had one instance of problem.
I can't believe that this is really an issue. And as Fotze just said, a lot of the information or stories seem to be blown out of proportion or completely taken out of context. (Or worse made up)
You can't start banning everything that is a danger to some people. Imagine what our world would be like if that was the case. No one would be able to do anything. I know other people who are just as allergic (deathly) to fish, black food coloring, other nuts, (PS a peanut isn't a nut, it's a legume...
) and other foods. Do we end up banning everything but processed soy products? Come on.
It's the child's and families responsibility to keep that kid safe. And of course, the school itself needs to be aware of allergies like this in case they ever offer food and probably SHOULD NOT offer peanut butter (or other offending foods) to any kids, to make sure there is no cross contamination. Should other kids and parents respect this kids condition and do their best to limit the danger? Of course. But should we start banning everything? I don't think so. That doesn't help anyone, including the kid with the allergy. Part of growing up is knowing what is serious and when you need to take care of yourself. And part of being a parent is learning when to let go and let your child do just that.
P.S. I realize this thread was originally taken from a thread on teaching handicapped children. In schools like that, maybe an outright ban is correct, but not in regular schools.