You fucking idiots, they don't want you to pay $25 000 000 for insurance, they require that you HAVE $25 000 000 in liability insurance in order to legally shoot on their property. Why? Because when one of you retards cracks their skull or busts their spinal column, they don't want to be held responsible, and can direct whoever got hurt's family to your insurance company. Allowing people to shoot on your property is a bitch, because without proper contracts and insurance, the schoolboard would be on the hook if any of you got hurt. Considering the fact that they can barely afford textbooks, they definitely can't afford a lawsuit.
They basically faxed you standard rates for shooting on schoolboard property. They'd sent these rates to anyone from tiny, independent movie producer to hollywood giants.
It's simple: you pay, you shoot, you fuck off. Or you do it the way it's always been done, i.e. you poach it, you shoot it, you fuck off before the cops show up.
Why do you think so much urban is shot at night? Because it looks sexier under the glow of car headlights and a crappy generator/home depot bought lights, or because it takes longer to get kicked out at night?