I missed this yesterday, so I apologize if you've seen it, but from FanIQ:
I don't advocate ever doing this. It's unbelievably improper and really punk. However, I will not be so high falootin' as to say that I've never had the urge to do this during the customary handshake at the end of the game. And I don't mean in Little League or AYSO since I never did either one. I mean like in adult league baseball and co-ed soccer. In adult league, it's worse because there's always some prick on the other team (or sometimes on your own team) that thinks that B-level adult league baseball is his ticket to the Show or that a hard but "clean" shoulder check to your wife or your buddy's girlfriend in the middle of a co-ed soccer match will get him onto the LA Galaxy.
And you know what that kind of guy deserves?
That's right. He deserves to be suckerpunched.
All that being said, I have no idea what the punchee did to deserve to get clocked like that, but if it came out later that the dude was talking inappropriate crap all game and doing generally punk little league things like grabbing jerseys on runners while they were rounding second, well then...