doesn't matter its not the like the kids actually hear it when they are playing.  I stopped hearing the stands by age 9 when i played.  This only bothers the parents of the opposing team.  I do think its wrong but it doesn't affect the game.

MyTwo:

You don't have that right!

The Umpire has control of only what goes on between the fences and inside the dugouts.

In the stands, he has little power.

I agree that I would nullify a balk incited by a fan, and the first thing I would do would be to ask the manager to attend to the deportment of his fans.  That's about as much as you can do. (Common Sense Fair Play!)

You could suspend the game if it got way out of control. And the next move is to get league officials involved if they are present.

Final move is to call the cops.

But you as the ump have no other authority. 

Fans have the right to be a$$holes, but proper application of peer pressure and a chance to make grown ups grow up is about all you can do.

Mike CVUA

If they're your parents hold a meeting and tell (not ask) them to knock it off:

"The kids aren't allowed to do it and we'd like you to follow their example."

Also let them know that their coaching during the game is confusing the players so you and the players would appreciate it if you'd leave the game-time coaching to the coaches on the field.

Make sure you smile and say "Thank you for your cooeperation."

If it's the other team's parents there's nothing you can do.

I told parents before the season starts the players will only hear one voice. It will be one of the coaches. I told them if they feel the need to coach their kids from the stands I'll pull them from the game so they can take them home and coach them.

As for opposing parents I told young players they need to tune it out since the noise will be there when they get older. If a parent was really obnoxious I made jokes about him to the players so they laughed at it. I told them things like that guy is making noise because he's upset there aren't any more boogers to pick in his nose. I told them the fat guy was upset the concession stand was out of nachos. Then I turned it over to them to joke about it.

"Total no class act..."

Hit the nail on the head.

Does it really surprise?

Where's the tournament director and/or the district administrator on all this?  They should be putting this league's Board of Directors on notice that this kind of crap is not tolerated.

When I serve as TD for our district games, I spend most of my time walking between the two sets of bleachers, making my presence felt with the parents.  If I hear anything that is remotely derogatory to the kids, I'll let them know they need to keep those types of comments down.

As for positioning their own players, that's an issue for the team's manager to deal with.  I won't get involved unless I know the manager is allowing parents to actually be an extension of his coaching staff.  For example, I won't allow a dad to stand beyond the opposing team's dugout giving base coaching instruction to his team's runners.  And I won't allow dads to set up along the fences strategically positioning the outfielders.