If some nut was blocking my car, I'd be inclined to be sarcastic.
And if the kid had to get to work, what was he doing standing around watching a bunch of kids attacking a woman with snowballs in the first place?
Hey, I was a kid once, too. I know better. The kid that got sprayed was a wise-ass who got what was coming to him. It's too bad his parent's didn't teach him when to keep his mouth shut.
I'd be inclined to take it away from her and put it in a place where she wouldn't be likely to forget where it was.