Always ask permission on private land. You could ruin it for everybody, no matter what you think. I would expect that to be the case any where in the world. As for schools, its best to ask. Some here wont allow it, especially during the school season. Your best bet would be parks. Even then, you have to watchout. A year back there was an incedent with someone flying over peoples heads in one of our parks. The county parks department banned all planes.
Edwin