I think I would call it more "popping" open/off, than "falling" off. Mostly it is when you are doing or lifting something- the end of the band which overlaps on top will catch on people and things when you are lifting a child, or a backpack or a purse etc, and it will basically cause the band to pop open. They also can get caught on railings, handrails or other outside objects. It isn't a huge problem, but it does occasionally happen, so you just need to be aware. We had the sliders and DH and DD still had theirs pop off a couple of times. The sliders tend to actually slide, or at least ours did. DH it was usually when he was lifting or messing with DD. For DD, she would be holding onto railing or something and it would catch on what seh was holding and pop open. It is basically just a peg in a hole, and I think as the hole stretches over the week, it gets a little easier to pop them off. Basically the end of the magic band that is on top and overlapping the other end catches on stuff causing it to pop off. I'm pretty sure we were all wearing ours with the Mickey facing away from us when we looked at our wrist so it would line up perfectly with the FP+ mickeyhead readers. We still had a couple of pop offs.