Maybe the crazy parents who are yelling at the players and other people should be banned. If somebody is yelling, the officer would eject them. That would prevent yelling and assaults. Maybe, instead of having handcuffs, the policeman could have a roll of duct tape. He could use the tape to cover the adults' mouths if they yell too much.
Youth sport are about having fun, making friendships, and learning the game.
The coach should teach. It's not about winning all the time. Before a parent yells, he should step back and look at the players. We weren't mad when my football coach started flipping out. Adults just need to grow up.