The horse is adorable. And I should like to try that with the bags tied here and there. My friend's horse is spooky about things around his flanks, and he bucked her off one time when she tried to take her jacket off while mounted and it brushed his flanks.
My trainer came and worked with him with a plastic bag on a whip, and putting it all over his body (him on a long leadline) . She does not care that he moves, in fact she wants him to move while learning to accept this . She started out tapping his shoulder with the bag and he would just stand there and flinch. He was stiff in his skin and his jaw was tight. He was "taking it". She doesn't want that, because a horse that just "takes it" but thinks that he is not allowed to move his feet , will get to the point where he cannot take it anymore, then he'll "blow up". She wants the horse to move forward , and accept the bag . So, she kept tapping his shoulder until he exploded, and she allowed him to move forward, and kind of kept the bag on his shoulder, just holding it there. The horse moved forward, and in a few steps, he turned to face her and stopped . She removed the bag from him. The idea is , you can move forward if you need to, and, when you calm down, we can remove the bag. Both are ok. She worked with him until she could put the bag on his flank and lightly tap on him to ask for forward, and instead of exploding, he just walked forward. So , he is not just taking it, he is OK with it, so she just removed the bag. He can walk forward calmly with or with out the bag. Both sides of his body, too.
Watching her work with him was amazing. I envy her timing. All this was done on a 12 foot leadline and rope halter.