Oh dear. What do you suppose might happen if you tie your horses head around and he freaks out? Broken neck, broken back, broken legs, permenently spooked horses terrified of being tied up... the list is endless.
Plus, how is that supposed to supple a horse? Woohoo look at me I can rip my horses head around and bind it there. Then I get on and he won't bend anyway. How does tying his head around condition the muscles and to strengthen and stretch?
It is the sideways equivalent of rolkur.
But hey, each to their own. Unfortunately everyone wants things NOW without putting in the weeks, months, of work. And this is the result.