And what time: most don't have a lot of kids in them at 4:00 a.m.
But even if the place is full of obnoxious kids and irresponsible parents, that's not a license for anyone to start hitting children. If a customer can't bear it, he can leave. If he wants to take effective action, he should first ask to speak to the shift manager or store manager to explain why he's taking his business elsewhere.
And for a grown man to hit a girl? Never.