For lo who sleep on mattress on the floor and on their own room, how do u prevent them from crawling and walking around the room on their own in the middle of the night?

I just let them crawl around the room (door closed) but I baby proof the home. I also wear an anklet with a bell round her ankle, so I can hear if she starts crawling. And I have monitor so I can watch baby :)

I will close the door because i feel it's hard to stop them from crawling , normally my kids wake up I will know because they sleep in my bedroom

Great question. We use a playpen around the mattress so LO cannot "escape"