Very interesting replies
I think I agree that the concept of letting them think the training over is pretty ridiculous. The horse isn't sitting there thinking "Oh! So if I yield to the pressure, then it goes away" At most the horse is thinking "That grass looks good. Maybe I can stretch my neck and get it"
I think I like it as more of a tool to create a buffer between the barn and the training. She could also learn to stand tied better. So how far away should she stand from the barn? I don't have a lot of property and until she learns to stand tied better, I should stay pretty close and keep an eye on her.
It is very promising to hear from those of you that have done this for a long while and now their horses can stand for hours. She could learn to have patience like that