Again, I am NOT saying they DON'T use hand/leg/body aids. I know they do. Even on a 'finished' world champion, I have seen them use a little leg to make them go/turn while working cows.
I AM saying that on a 'finished' cutting horse, you will not see many people using their hands much. They work the horse mainly off their body, I.e. Steering them with leg, seat, and spur cues in competition.