I’ve done a few hundred deliveries over the last couple of years, I left one on a porch swing once on a rainy day… I got 2 blocks away and than realized it wasn’t next to me in the car and drove back and got it. Not sure how they disappear but I read about them going missing often. Aside from that one instance I never came close to losing one.
I also use bag solution, I have a few that the velcro went out on after a year or two and they’re piled on top of the walk-in somewhere. I’ll have to check out the Hobby Lobby solution to see if I can re purpose them, as it sucks to trash a perfectly good bag because of the velcro.