I’ve read that some of the bitless
bridles have a problem with the straps underneath the jaw not releasing quickly
enough to let the horse be quickly rewarded for doing what you ask, therefore
causing uncalled for pain, pressure, and confusing them. Also, I believe there
is a “learning curve” for the horse to understand what is being
asked with the bitless bridle even when the straps do
release quickly. I think that the flat straps get hung up, and that the rounded
ones release quickly, maybe, but just going from memory. Anyone have any direct
knowledge, mine is just “what I’ve read”.