No, that's child molesters you're thinking of. There won't be one convict who hasn't wanted to do the same thing.
I agree it's wrong to hit children, especially when it's really the parents fault. What I suggest is that only the parents are hit. Any time a child is screaming or otherwise is uncontrollable in public, anyone has the right to punch the parent in the face, right there and then. It could become a public gauge of their parenting skills. And I would be really interested to know just how many popknots you show up with Viz.