My office had something similar to this a few years back, except they gave us this absolutely pathetic cheap pedometers that you clip onto your pants. You could shake it with your hand and it would count it as steps. The winner would receive like a $50 gift card to the local running store and like a half day off (or something similar). Contest lasted 6 weeks. Given that I am (arguably) the only higher mileage runner in my 500+ person office, I figured I had a legit chance to win.
At the end of the first week, I had run 75 miles and (assuming 2,000 steps per mile) had 150,000 steps. I got ABSOLUTELY CRUSHED in the numbers. The lady who was leading the contest, who I knew of (didn't work with her directly), had something like 312,000 steps in the first week. Possible, yes, but for a (at the time) probably early 40 year old lady with a couple of kids and some extra pounds (not obese, but definetely extra weight), I was highly suspect.
I knew right then and there that I had to not care at all because for me, being fit and in good health is an everyday thing. It's part of my life. I don't do just do it for a contest and then Week 7, Day 1 go back to binging on oreos and taking the elevator down 1 floor in the office.
The funny thing is, a few weeks after the contest began, someone from our wellness committee (who knew I was a big runner) asked me if I was participating. I replied back that I started to, but decided after the first week that the contest was complete bs and that if no one was going to monitor the legitimacy of the numbers, then the contest was flawed. I was asked what I meant by that and replied that "if you really believe that so-and-so is doing 300,000 plus steps per week, which is over 150 miles per week and has been doing so for the last 3 weeks, you are only fooling yourself".