Parents at Games
Ideally, the coach will make it clear at the start of the season that loud, boorish, or obnoxious behavior is not acceptable. The majority of moms and dads understand this concept and keep their emotions in check.
If you encounter a loud parent in the stands, diplomatically let the coach know the parent in question is becoming bothersome to others. If the coach doesn't respond, then consult a league administrator, or even the game official. Officials generally have the ability to vacate or reprimand an out-of-control parent.
Some leagues employ a "zero-tolerance" policy in which officials can stop the game at any time and demand that a verbally abusive parent leaves the gym. If the parent doesn't leave, then the official usually has the option of forfeiting the game to the opposing team. While this may sound like a drastic step, zero-tolerance policies have made a significant difference in the behavior of parents.
Approaching an Out of Control Parent
You have to be careful about confronting other parents, particularly with children around. Confrontations between parents rarely have positive results. Too often, in fact, they escalate an already volatile situation. The fact that a parent is yelling and screaming at a youth basketball game suggests he or she has lost perspective and isn't likely to negotiate. If you make an attempt to quell the situation and nothing is resolved, back away until the parent calms down.
If the coach doesn't have a printed list of what will and will not be tolerated, then ask him or her to create one. All parents need to be aware of the expectations of the coach and the league.
Try to Avoid "Parenting" Your Child's Teammates
Get to know your child's teammates. It will be fun for your son or daughter to see their parent talking to their on-court friends. But try to avoid using that new relationship to "coach" or "parent" your new friends. Leave that to the real coach and the teammate's parents. If you witness behavior by a teammate that your are uncomfortable with, explain what it is you do not like to your own child as a lesson. If poor behavior continues, mention it to the coach, away from other parents, to see if he or she is aware of it and if they can do anything to change it.