Let's think about what really happened here. The owner brought a horse that he couldn't handle to a respected clinicians wife. The clinicians wife did her thing with the horse and helped the owner work on the horse as well. In the end the owner was happy, the horse was easier to handle and had not been injured or abused and is now a nice riding horse for the owner. I don't know what better outcome you could ask for. Even if you don't agree with what happened in the video (I think alot of you are not watching objectively) the outcome was good for the participants involved. I am confident that now the owner doesn't need to whack his horse with a metal clip when backing his horse so whatever degree of discomfort the horse experienced has been over for years. After watching the other two videos that come before and after the original video I am even further convinced that what happened was fine. I wouldn't have done it quite like she did but it worked and now all parties are happy. If you don't like it don't do it but more right happened there than wrong.
P.S. I still don't like Parelli but I hate to see someone unfairly demonized. Critique all you want but do so with your emotions under control.