There are some who are truly anaphylactic to nuts, but most of those people know to stay away from anything that might even remotely have come in contact with anything that is nutty. These are the people who carry an Epipen on their persons in case of an encounter.
We did not have nut or peanut specific items banned when I was in school (class of '87), but I am sure it is a CYA move by the schools over liability concerns because they can't keep little kids from sharing or touching each others food and hands, etc.
But, it does make me wonder if changes in how peanuts are farmed over the years has caused the rise in the true serious allergies to nuts. It might be more accurately a reaction to a pesticide used on them or a component used in harvesting in more recent years compared to 40-50 years ago.
