So I've read plenty of threads where we can all agree that we aren't going to take any crap from coaches and at a scholastic contest we are going to ignore anything said from the stands.
I recently had a contest where the Varsity coaching staff sat in the bleachers and yelled obscenities at the JV/Fresh officials when the varsity coaching staff disagreed with their calls. You could obviously tell they were coaching staff and represented the school as they all wore matching shirts and were sitting just above the team bench so they could coach (yell at) players as well.
The things that were said I would consider an "Automatic" had the coach been on the court but I would have ignored if it were just the common fan in the stands. Needless to say though, it still definitely violated the NFHS sportsmanship policy.
I think it would be looking for trouble to T the bench in this instance, much like it would be trouble to tell game admin. that the varsity head coach has to leave the gym. I am interested to see what the peanut galleries opinions could be to help resolve a similar situation.