Even the DU tv announcers acknowledged why Cagiulla retaliated with the punch (the textbook horse collar) but, as they said, the refs will almost always get the guy who retaliates.
I will bet that UND has learned a hard lesson in DU's style of play (the dives, embellishments, etc) and play a smarter, more disciplined game. God knows, we won't be given any favors by the officials so we better darn well do our best to stay out of the box.