Just tell them "Rule 10"
At a 14U ASA National some years back, I was PU and one of the teams was from Florida and totally obnoxious. The Dads and Moms in the stands had those long plastic horns, cans full of rocks, cow bells, boom boxes, you name it and they were VERY distracting to the other team as the devices were being used constantly, not just between inning music. However, I didn't say anything until the opposing coach came up to me between innings and complained. I mean the stand folks were AWFUL! My 2 ps and I were sick of them!
I went over to the coach of the Florida team and relayed the information and asked him to tell his parents to turn off the music once the teams took the field and don't use the horns, etc., on purpose to distract the other team under Rule 10.
He agreed, but unfortunately, several of the Dads did not.
I told an off game blue to get the UIC and continued the game. Next 1/2 inning break, I explained to the UIC the problem. He went to the coach, 2 Dads refused to comply and they were escorted to the parking lot by the police on duty.
No more problems with this Florida team. BTW, they won by 1 run, but at least the other team had an equal opportunity.
...and if you don't agree------
I don't care! The UIC thought it was the right thing to do.