I wore a Fitbit on a recent flight, on way out I set off the alarms and had to step into the x-Ray machine. It showed up my Fitbit & the two zips on hip pockets of trousers, so. Had to be 'patted down'. On way back different trousers, but I still kept Fitbit on, no probs at all. Was planning to travel to Disney in the same trousers, as they match new Minnie Mouse T-Shirt, now re-thinking that one