RE: Safe to fly in school yard?
I was flying a HLG one day at a local park, when a Police car drove up to tell me he'd gotten a complaint about my airplane making too much noise! While I talked to him and asked him exactly what noise I was making to complain about, I flew the plane about 10' overhead. I eventually landed it (it was getting toward dusk anyway) and showed him completely that the only thing that could make any noise was the servos, which he had not heard from 10 feet above us. Then I told him he should contact the person who called the police, to remind them the police department was not there to help them press false charges!
He thanked me for my frankness and honesty and bade me a nice evening.
That was over 20 years ago, proving that jerks are not new to this generation, nor any other. Just fly safely, and abide by the actual rules.