MERCEDES has sparked a privacy row by admitting it spies on drivers with tracking devices covertly installed in its cars. The secret sensors, fitted to all new and used motors sold by the firm’s dealers, pinpoint the vehicle’s exact location. And it insists they are only activated in “extreme circumstances” — when finance customers have defaulted on their payments. But it admits sharing car owner information and vehicle location details with third-party bailiffs and recovery firms who repossess the cars. But Mercedes customers who buy cars through the official financial arm give their permission when signing lengthy terms and conditions...