As a field engineer, our bosses decided not to follow the copy a local firm providing engineers for telecoms work with GPS tracking in the vans, and automatic reporting of where and when the vehicles stopped. The idea being to save engineers filling out logs for the vans with mileages etc.
What they failed to realise, until they dragged the first "victim" into a meeting to discuss his undocumented visits to non-customer sites and showed the logs from his van, was that every time the van engine did it's auto-stop/start thing at traffic lights, the tracking software registered a "STOP" and assumed it was the van being parked . . . None of the bosses in the chains had spotted all the "unscheduled stops" were in areas with heavy traffic and with traffic lights . . . DOH !