No one has mentioned this yet, and at risk of reheating the debate, I was really pleased with the way Kelly handled the situation, by his response to the question in the Pitt press conference.
When asked about it again, he didn't play it off. He didn't preempt it, or act apologetic.
He simply stated that Grimes and the bench had been warned. Made no excuses for the way he reacted. Stated that he was the one responsible for the ND sideline, and that he wasn't going to allow the team to get an avoidable penalty in that situation.
He held no pretense of self-justification, he just simply stated the facts. He implicitly if not explicitly agreed that his behavior left something to be desired.
He then made it clear that he had conversations with his superiors, and with David Grimes about the whole situation.
He then smiled and said that David would be with the program for years to come.
I liked it. Hopefully it will lose some traction, and eventually go away.