I don't want to start a fire here with any added friction, however there is no safety bead strong enough to keep a underinflated tire on the rim, especially on a 500lbs motorcycle with twin rotors up front. It may help you get to the side of the road, with your seat wedged incredibly high between your cheeks, but you are not rolling away under power until that tire is inflated again. Underinflated may be subjective and the exact pressure could be different from tire to tire the only way to keep an underinflated or extremely under inflated tire in place would be a bead lock system that you see on rock crawling 4x4 vehicles. They don't have such systems for Tubeless motorcycle tires( that I know of). If you are running low pressures you should have a tube or mouse(not recommended for road use) and a Rim lock to prevent your tire from slipping on the rim and slicing off the valve stem of a tube. Please be careful if you are dropping pressures below the recommended ranges especially after you have converted to tubeless or have tubeless. I would bring a tube along for the ride out if you accidentally find out what the threshold for your bead is. Again I am not a pro or a mechanic but this is all from my general knowledge and my personal experience(which is limited in comparison to many other members here). Ride Safe!!!
