I agree, you could also hear the director with a "mike" talking to the kids. I actually heard a director say "you've got a job to do..this is your chance, yadda, yadda, yadda" all of this going on during the peformance of the band playing on the field. Very distracting for not only the band, spectators but I can assume also the judges.
I understand this is their first contest, but it's like a new resturant in town.. you don't get many first chances before people stop coming.