These kids were bored, and have nothing/nowhere better to do/be then wind up others in the park. In my experience on kids generally being fools in places like this had the ball gone anywhere near your kid it would have been, "Ahhh, Miss. Im well sorry, it was him, we didn't mean it. Is he ok. Soz!" It's a shame, not a crime, and not a reflection on "broken britain," or whatever it is that's been hinted. Were you never a kid? Or were your childhood days spent well mannered wih exemplaty behaviour skipping in the front garden? do only the deprived, dragged up kids play football where there not supposed too?