There was no way you caused that horse to learn a bad habit in only a few minutes. The horse was obviously agitated before you mounted. Even if she is deranged and really thinks you caused the horse to start rolling with your animal telepathy, a good instructor doesn't scold a student for doing something wrong. A good instructor teaches you what to do in the future, not blame you for messing up the horse. Don't give this woman any more of your hard earned money.
If horses learned new behaviors after one attempt we'd never be able to ride most of them!
The trainer is clueless. The only thing that helps the horse is when the rider is in a good state of mind (calm and confident) because horses can pick up on nervousness, anger and more and it can cause a reaction out of them unintentionally. Posted via Mobile Device
Horses that have developed a relationship with you DO know what you are thinking, sort of. It's a little like the tv series, "Psych." They observe you so often, that it's hard to fool them. They really do know JUST what you're going to do. Dogs that live with you are the same way.
Ditto w/ stupid instructor, blaming YOU for her own lack of horsekeeping.
Most people don't expect a horse to roll while mounted, so the first time it takes you totally by surprise. You know that the horse is doing something strange, but it doesn't dawn on you what until it's too late. Once you can recognize what they are starting to do, a good way to stop it (before it goes too far) is to *insist* on forward motion (kick the snot out of them). Of course, you should immediately try to figure out why they did it.
While out on a trail ride, some horses will instinctively try to roll when you cross them over water. It's not a good idea to leave a saddled horse untied as many will roll with the saddle on and break the tree. One horse we knew had developed the habit of rolling as soon as she was mounted, just to see who was in charge ;)