i long for the day that the bitted/bitless debate is resolved using sound mechanical and biological facts, rather than using individual examples of horses and personal experience of riders.
and on that note:
yes the pressure will be in different places, but X pressure in X direction can always be clearly distinguished from Y pressure in Y direction, regardless of bitted or bitless. this is a simple mechanical fact because there is nothing about bits through the mouth or nosebands around the nose that impedes the transmission of a changing or constant directional pressure...
so explain to me how there is any difference in precision, without telling me about a horse.
Well, a loop of rope hanging around the nose does NOT mechanically give the direct, focused cue that a bar across the jaw does. Imagine holding a bit in your fist. You will feel slight pressure on the bit far better than you will if someone puts a rope around your fist.
It works that way with horses. Yes, a rope bitless bridle WILL allow you to put their face around even when they are excited. However, it will NOT allow you to use a lagging rein. By that I mean take an excited horse and as each shoulder moves forward, lag with the rein on that side. Don't pull BACK, just move the rein with your little finger a hair behind the horse's shoulder moving.
Horses understand that as 'don't move that front leg so far forward in your stride'. That is what I was told, and it worked like that with my mare who had NOT been given any training on it. We worked with it at a walk and at a trot. Now, when she gets all wound up about cantering and either wants to move into a canter while at a trot, or wants to string herself out on the front end while at a canter, I can use a lagging rein to 'collect' her. Not to put her into a collected gait, but to keep her moving with her rear while her front end takes slightly shorter front steps, balancing her and relaxing her.
This proved invaluable when I needed to teach her to canter with a rider. She was clueless, and our first few attempts were dangerous. She had her nose inches above the ground and the vast majority of her weight on her front legs. She was flailing, and it felt like we were going to flip arse over tincups.
You cannot do that with a rope circle around the nose.
You also cannot turn the rein like you are starting a car with a key, and have the horse respond by keeping its shoulder up. They just do not feel a rope sliding on their nose with the precision that they feel a bar across their jaw. A rope halter, and I rode with them exclusively my first 3 years of riding, just is NOT mechanically as precise.
Take a look at this picture. Notice where on the horse the rope halter is working, vs a bit in the mouth:
The same is true of pulling their head to a more vertical position. Pull both reins back with a rope halter, and it will first move up on their face. That is not nearly as precise as a bar located in their mouth near the tip of their nose. I am NOT talking about forcing a horse into a frame. I'm talking about getting a very excited or frightened horse to yield.
A rope halter, even if it is designed as a bridle, is NOT as precise and does NOT give the leverage that a bit in the mouth does.