If the same thing happened at a public park and one of our 100 kph 2 pound plastic foamy toy warbirds
That is the problem. If you are flying a 100kph(60+) miles an hour plane in any park with people around you are wrong. Do some of my birds fly as fast/faster than that? Yea but the only time I use full throttle are really high passes or full throttle accents. Even then I have a fail safe that if I lose signal kills the throttle so its not full power when it hits what ever its going to hit.
And I used to fly at a soccer field all the time with people on it, but only with my radian. Only then would I say its acceptable to fly over people.