I find that when my small grandchildren are sleeping, they squirm around so much that they end up out of the sleeping bag and on the floor with no warm covering.
So what I started doing was opening their sleeping bags like a blanket and then covering each one with their own sleeping bag. Then what I do is take a blanket and comforter and put it over the children and their sleeping bags.
This way, when they move arond in the night, they still have something on them. Plus, have you ever tried to put a sleeping child back into a closed sleeping bag in the middle of the night? It is no picnic - LOL
So this is much easier for me as well to get them covered up.