This happened at my local park recently.

http://vimeo.com/m/39135997

The guy was interviewed on the radio and on TV and said that the guys and kids he hit were being douchebags before the camera went on. By listening to what he said in the interviews you could easily tell the prick was lying. He got a fine in the end of about I don't know how much, but he thoroughly deserved it.

(vid doesn't want to embed cos I'm on my Iphone)