Mine fell off several times but only when I picked up my grandchild. I didn't have a slide.
I would also be careful when putting on/taking off jackets. That is when I tend to lose my fitbit, which has a similar band.
Never had any problems with our MB's....they gave us band keepers our first trip .... with the year....this trip MB's keepers say Passholders ....very useful item to keep band tab from pulling up...