During timed events such as break-away, tie-down and team roping, as well as steer wrestling (bull dogging), the steer or calf leaves the chute with a head start advantage and trips a barrier line with a red flag attached to it.  

This signals the competitor to commence his or her event.  When the competitor leaves the box too soon the barrier is broken and this adds 10 seconds to their time.  It is the Barrier Judge's job to let the timers know a penalty has occurred.