I, like most allergic readers have read on blogs and forums the theory that nut bans, and milk free tables are ridiculous. One common miss guided statement is "What next are they going to ban school yards in case someone is allergic to wasps".
When I was a kid in grade school, a child had an anaphylactic allergy reaction to a wasp sting. The child was given allergic treatments and rushed to hospital via ambulance, he returned back to school fine, a few days later. I don't remember the details here.
The recess, after the sting, the back of the school field was "out of bounds". The next day they had some sort of wasp removal service come to inspect, and remove wasps from the bushes with the wasp nest.
An announcement was made that the bushes where officially declared safe by the service, and the field was opened up to the students. When the back field was "out of bounds" teachers and volunteers guarded the back of the field to make sure no one would enter it, or near the bushes where the wasp nest was hiding.
So yes their is such thing as a wasp free area of a field, sort of like a milk free table, or nut free table. This was sometime ago, I was in grade school at the time.
I still don't know if this is the school board policy, or just the principals decision.