That is not he same as scenes where they are riding in new territory around cliffs and sheer dropoffs. The horses will not just steer themselves where people want them to go. The humans on horseback could not just steer the horses around such obstacles because they can't see!
Have you ever ridden horses? I have ridden lots of horses. I grew around them in farming anf ranching communities. Horses have minds of their own and do not always do what you want them to do. Even the best trained horse will test your authority and see what they can get away with.
Then to be honest a horse going around in circles ona track in a controlled environement is not the same as horses in rough uneven terrain in the wild somehow going in a straight line as they do on this show.
It’s not real