That very well may be, but in this case it was a little kid. Now, I'm all for the right to self defense and all, but the rules are totally different when the offender is a little child. If a grown man, or even a punk teenager starts crap with a character then, I can agree that the character has a right to defend himself accordingly, even if it means knocking the punks block off.
But in this case, it was a little CHILD for Heaven's sake. Even if this child kicked him in the shin or even the crotch, you can't go chasing down a child. What's he gonna do when he catches him? Beat him up? Now I'm not saying that it is okay for kids to do this kind of stuff just because they are kids. But the proper way to handle it in that case is to deal with the parents about their child, not go chasing a child around...in a character costume no less. That's just opening the door to getting canned from your job, not to mention all kinds of legal trouble.