Maybe the MRI equipment along with other wiFi , cell repeaters , two way radio transmitters etc are the problem they are trying to warn you about ? I know I can fly fine everywhere around my house but can't get within 1/4 mile of the hospital without a bad signal message .
The schools and power plants are just common sense to stay away from .
1. It depends on the local school district. Some or more strict than others when it comes to usage of the property during non-school hours.Aren't schools great places to fly? When the building is empty, we are left with giant open spaces. Where I live, school grounds are treated much like public parks. There are baseball, soccer, and football fields which are open to the public, unoccupied, and wide open spaces most of the year.