Annoying People
One way of looking at it.
This would warrant stopping and making sure he never does that again. I had some kids spray me with a hose once. I saw it coming but played along. I did come back around and tell them that they could hurt someone spraying them and surprising them.
The Mom saw me talking to the boys and came out and started scolding the boys and apologizing to me. I asked her not to be hard on them.
You see, it was Karma. I did this to some motorcycle riders when I was a kid.