Maybe its just a difference in how each individual barn is run. Good and bad things happen everywhere. At the place I volunteered, if the rider was physically able to ride without a sidewalker, then they had to ride properly. Not necessarily posture wise, but they weren't allowed to pull or kick at the horses. If they did, they lost their bridle and the horse was led again.
Conversely, I worked at one dude ranch (not for very long, let me tell you) where the guy only had 10 trail horses, and they rode every trail, every day. You would ask people to not yank at them, but they paid their money, and figured they knew how to ride. Not a very pleasant place.
But the other dude ranch I worked had about 40 horses, so no horse would work 2 days in a row.