My only thought is that this was a very very short procession. Maybe 100 yards max. Where I was standing to take the pictures was where all the bands stopped and disbanded to make room for the next band. My guess would be that they were giving orders to halt....but I thought the drum majors did that... There were also lots of judges with clipboards standing along the line of march so maybe they were making sure the band members were properly dressed (in the line of march sense of dressed).