Why you should not use a full cheek without keepers. Or at all if you ride Western.
The long prong like sidepiece above the mouthpiece can catch on things, like a stirrup, your clothing, stick off a bush trail riding or some bit of tack on another horse. The keepers aren’t like keepers on other bridles , they go from the top side piece of the bit to the cheek piece on the headstall to prevent anything from slipping over the top and getting stuck or getting hung up on something.
This is not some bogey man story to scare you or one in a million chance at catastrophe. It happens. My worst experience was trying to catch a hunt seat Pony, young rider was leading it, didn’t know nuthin bout no keepers. As kid entered the arena, she pulled her irons down and turned back to close gate, Pony went for fly on its belly. Top of full cheek caught on iron, hung up, Pony could not pull head around, panicked, tried to bolt but spun around and around, right over top of kid. Eventually it fell over spinning, otherwise we never would have caught it. That did not need to happen. Yet seen it other times, just didn’t need to catch it. Also seen it catch on somebody else’s iron or stirrup, one case a breast collar when the two horses were sniffing each other. Totally avoidable.
If riding Western in one without keepers? You do realize you generally will have slackin the reins and horse can shake its head and get the reins caught over the top of the side piece? You have to get off to flip it back and have no brakes or steering until you do. It’s not a very good choice unless you rig some kind of keeper, they don’t make them for Western headstalls.
I have read a theory that a flat sided snaffle helps with steering? And it does, when riding on contact applying the direct rein, the flat side of the bit on the opposite side is pulled against the opposite side of the mouth. But Western horses aren’t ridden with constant contact and direct rein is not a preferred choice. The goal us not needing two hands on the rein. Even English horses depend more on leg and seat then an active direct rein…the flat sided bits like dees are fashionable, accent the head on bulkier WBs, not really functional as far as needing more steering goes. Full cheeks are seen but not preferred as they indicate horse needs more control steering wise. And they have keepers.
There’s quite a number of so called Western snaffles out there, you can buy a little gadget or stick a curb strap between the rings under the chin or use a piece of baling twine to avoid pull through…and teach the horse to steer and stop with all aids first.