Clearing the first row of bleachers

[Robmoz]

I've had a couple of situations this season regarding large crowds in smaller gyms that allow seating of fans in the first row of the bleachers which made it quite distracting to run up and down the sidelines during the beginning of the game (as more fans filled the stands). I had to ask the site admin to have the first row vacated and in both instances my request was met with a lackluster effort to move the fans. Each time I had to insist and ended up waiting for compliance to my request. I hated to hold the game up but was not willing to risk a collision or worse yet, an injury to myself or a fan.

Q1. Is it acceptable to request that the first row remain vacant?
Q2. Is it prudent to mention this to the table prior to tipoff when you see a packed house or just wait for it to happen?