..
I'd be surprised if that scenario could occur without a warrant, or a very stupid employee. Even if a GPS trail from a work issued phone showed that a "sick" employee wasn't huddled in their bed during business hours, it would require more than that to establish they were dodging work. "My back was sore, and the only seat I found comfortable was behind the wheel of my car, so I spent the day driving around to take my mind off the pain."
A geotagged photo taken with the work phone showing Mr. Sick competing in a tree climbing competition out of state might be a different matter. : )