"As parents, we have to model the lessons we want our kids want to learn," he says.
There are other good reasons not to interfere, says Malcolm Brown, a high school and club soccer coach in Westchester County, N.Y.
One of his teams has instituted very occasional "silent Sunday" games. But he'd like to have them more often because he says they make his players better — and more able to make decisions on their own.
"Too often during games, they're looking to the side for direction," he says of this generation of young athlete. "They become robots. They can never become good in soccer because soccer demands the imagination and creativity of the player."
Wendy Grolnick, a psychology professor at Clark University in Massachusetts, sees why silent games could be useful. But she also says coaches and leagues shouldn't punish all parents because some are overzealous.
"We don't want to just shut people up and make them feel like they can't say anything," says Grolnick, who wrote the book "Pressured Parents, Stressed-Out Kids: Dealing with Competition While Raising a Successful Child."
She recalls her own experience at meetings for parents when her daughters have played field hockey and tennis in college.
A lot of those meetings focused on "what not to do," she says. "It could feel a little insulting.. We need to feel like partners in the process."
But there's a happy medium, even for the most well-intentioned parents — and even when they're not yelling or fighting — says Mike Cherenson, a youth sports coach who founded a lacrosse league in his town, Pequannock, N.J.
He tells the story of a first-grade soccer game, when a young goalie was having trouble stopping the ball. Her mom ran onto the field to block it for her.
"Everyone had a good laugh — no harm, no foul," Cherenson says. "But I think it does depict a larger problem.
"There seems to be an inability to separate yourself from your child."