We used them last month (ages: 6, 11, and 3 adults). My dd (6) lost hers one night...not sure when or how, but it was gone when we got to the resort. Had to go to the front desk and they issued her a new one. Another time when I was picking her up her band must of caught on my shorts and it popped off, but we noticed right away and just put it back on. Mine also popped off one day when I was trying to get something out of our bag, but again it was very noticable and I just put it right back on. Overall, I'd say they're pretty secure, but I feel like you do need to be mindful of them, because they really aren't that hard to get off either.