As a field volunteer on the blue side, we were told that all balls that were "misfired" over the top of the player station, were supposed to be dropped into one of the bags for the human players. If the balls were shot over the side walls, they were supposed to be thrown back into the field of play. I personally can't speak for the red side, but on the blue side, I guarantee you thats how I returned the balls, and I was there for 95% of the matches.