Earlier this season (maybe at one of our games) the ref asked the band not to play as the teams were at the line of scrimmage. There is a rule that band/PA music is to stop before the offense starts calling signals. But I've never heard it used against cheerleaders. Maybe they were yelling "Omaha, Omaha."
I thought the rule was that the band and/or loudspeaker musak had to stop when the referee signaled the ball ready for play and the play clock started. I've seen it go on several seconds after that and have worried that we might get a penalty called on us at times.