Fitness trackers can be tricky
When I was working for Yahoo, Marissa Meyer decided to give the entire company fitness trackers from another company of which she was a board member and institute a "100 mile" challenge for employees: we needed to walk at least 100 miles a month. Some people really got into this, with my director winning with 25+ miles a day by dint of fitting a treadmill to his desk. I was cycling to the office anyway, but the 18 mile round trip only ever showed up as 6 miles of walking, until I took to fastening the tracker to my ankle instead of my wrist, which caused the mileage to double.
Still didn't win any prizes though!