I’ve NEVER spent a night in jail, so I have NO clue what they do there. My guess is that they really don’t care whether or not you fall out of bed!!!
My local hospital has rails attached to the bed that they pull up & lock at night so it’s pretty much impossible for a patient to fall out of bed. I think that once they pull those rails into place that you only have maybe 12 inches or so near the foot of the bed where you can actually crawl out & even with that open area, it’s still almost impossible for you to fall out. Of course, I’m assuming that you’re worried about falling out of bed!!!