Wow, this is so hard to understand. But after reading the 13 pages to her other thread about needing help, I think if I was a barn owner and I had a horse that acted like that I would want the horse out of my barn too.
I have to ask, does the new place you are going to know how dangerous your horse is? A rearing horse is a hazard and YOU are knowingly bringing such a horse into a new barn and as a mother or 2 young girls that are at the place we board at I would be livid if there was a new horse brought in with such serious issues.
I just had a friend that was keeping a pony at her place, this pony was a witch. A little girl was in the field with her mom and a few others while they were putting a lean too up, the pony kicked the girl in the mouth and broke her jaw. When my friend called the person who owned the horse, my friend did not even have to tell her which horse kicked the girl (she had several horses there). She knew and worst off she was not surprised because she knew something was wrong with this pony and did not tell others.
When you give a personal lesson in meanness to a critter or to a person, don't be surprised if they learn their lesson.