I would talk to them about what the possible repercussions of their actions are. "how would you feel if his facemask broke and he was injured" let them think about the consequences of their actions and how a decision like that could possibly play out. "are you willing to put a guy in the hospital for not giving you the zone you think you deserve", I'd talk to the parents too about how disappointed I was. Then I would either a) suspend them for some length of time if this was a first offense or b) kick them off the team if something similar had happened before.
but....this is all hypothetical because it was little napoleon who ordered the hit.
I still think the whole kerfuffle is amusing and just another day in the life of crazy, and I still think the ump was calling a punitive zone and when those few bad umps do this they are setting up a situation where all it takes is the wrong guy in the dugout or the wrong girl behind the plate and this little slice of stupidity happens. So it is best if people just behave responsibly so the darker sides don't come out. Coaches need to keep themselves in check, umps need to stay as fair as possible and players need to know when their coach is out of line. I don't view this as a right/wrong single action event, I see a situation that spiraled because everyone involved was a douche.
Man you are trippin... You need to get the duck hunt shoot planned. LOLL