If a child is so allergic to peanuts that he may die from talking to someone who has recently eaten peanut butter (not saying this is the case here, but it is the case for some children), then they should not be out in public at all.
An allergy of that type of severity can only be controlled by control of your environment, not by your own behavior.
For example, let’s say little Billy is allergic to peanuts to the point that inhaling a minute amount of peanut dust will cause him to have a severe reaction. Little Timmy sits next to him in class. The night before, little Timmy went to a baseball game and got a new hat and a bag of peanuts. Little Timmy wears the new hat to school the next day, and it has peanut dust on it. Little Billy asks to try on the hat and gets peanut dust on himself.
Now, no matter that peanut butter is banned from school due to little Billy’s allergy, he has still come in contact with the deadly allergen.
That is why bans on one source of contamination are counter-productive. It creates a false sense of security.
Spot on, except many of these bans are authoritarianism masquerading as compassion. As always logic and results don't enter into the picture.
Your "false sense of security" also applies to the TSA pantomime currently appearing at major airports nationwide. Nightly shows & matinees 7 days a week.