Can you stuff a backpack in this pad without...
Can you stuff a backpack in this pad without it falling out?
Securely? Yes. Guaranteed not to fall out? No. There is the one strap on the bottom to tighten down the pad, but it does not guarantee that things won't fall out.
As said its not a guaranty but if you pack it right it should stay in, small things in climbing shoes, clipped to harness stayed in for a 30 minute hike to my last boulder.