Ever paticipated in planning an air show? Well you have to submit a waiver, along with a plan. Our plan included closing of many buildings with no occupants in the buildings. So if their is a crash nearby then there are no people in the buildings. Traffic is reroutedetc. Then the pilots who fly in the airshow must have an Aerobatics Competancy test and form before they can be in tha airshow. So the risk is much smaller than alow flyover over a stadium by your normal military pilots.