I would not be surprised if all new leases are fitted with a tracker, and existing lease to be fitted with a tracker at service time. To best honest it doesn’t bother me if they fit one.
It wouldn’t bother me either, as we have nothing to hide. However, as I’ve posted elsewhere, I can’t see them fitting trackers to cars where the only drivers are the benefit recipient and / or those who live with them. In these situations a tracker would be pointless, as a tracker won’t tell anyone who is driving and / or what the purpose of the journey is. In these scenarios a tracker would add to scheme costs for no benefit.