The other day I went to Six Flags America in Maryland and had something similar to this for ride reservation times. You'd hold it up to a machine to choose a ride and time, and the machines were scattered throughout the park. They were tight enough to stay on easily, but made of a stretchy material so they could be removed. I would object heavily to a non-removable bracelet, even if it was waterproof. I simply would not want to wear something like that nonstop for multiple days, and I can't imagine it being popular with children (or their parents).