Why their phones but not all their other sources of information, entertainment, education, etc? That's why it was arbitrary.
Why this game and not every other game during the season? That's why it was capricious.
What about an 18-year old, adult player? Demanding his phone randomly be turned over, and then excoriating him for not complying is an attack on his independence. I don't care who is paying for the hotel or trip.
What if a university demanded a recruit turn over his cell phone while on an official visit? They want the kid to focus on the experience, and not be distracted. Would that be okay? It's absurd.
I mean I understand the intent, but the implementation was 100% wrong in this case. The right thing to do is tell the players not to post on social media, and if they do, then they risk being suspended for the game. I have no problems with that restriction, especially if the rule is disclosed in advance. But to get through the entire season never taking their phones the night before a football game, and then to do it before the last one, is mind-blowing to me.