I tried to explain it in post 6, but I’ll try again :).
It works pretty well with spooky horses that drop & spin.
When the horse moves away from the expected travel and your body can’t follow the horse’s movement, when you have the RS-tor in your hand, your hand will stay exactly where it has to be, at the withers, sucking you back towards the saddle, even moreso because ones body tends to tense up when a horse does something unexpected, locking your elbows.
Very often when a horse does a 180 degree your hands will not be near the withers anymore, more likely up or even crossing the neck. Having hand & elbow where it should be in order to follow horse’s body gives you more chance to rebalance quickly, following the horse’s unexpected move and correct.
It won’t glue you to the saddle, you still have to ride thru the issue, a non-rider or inexperienced rider shouldn’t expect it’ll allow him/her to ride a bucking bronco all of a sudden, but it gives you a better opportunity to follow & correct instantly.
You can lengthen and shorting the strap, I ride with it as short as possible, which gives me most benefit I find. Even at it shortest it will not interfere with your rein-aids at any other time.
I don’t think a video can really show the feeling it gives you.
Will it help in a spin, buck, rear etc. yes. Will it help when doing a one rein stop during a bolt yes.
It helps in those moments your body risks not being able to follow a sudden unexpected movement. In a bolt you are still able to follow the movement, you just can’t stop it.