This may be the single most important safety factor for service technicians working in a shop where there are hybrid vehicles because the hybrid system is silent when running on battery. Hybrid systems can automatically turn themselves off and on, switching between the high-voltage battery and the gasoline engine, so it is easy for the technician to be unpleasantly surprised that a vehicle thought to be 'off' is in fact 'on.'  Zaidel recommends observing these service protocols:  A hybrid is not necessarily powered off until it is verified that the vehicle is powered down.  Keep vehicle keys a safe distance from the hybrid - more than 20' - as many hybrids have a keyless ignition, with on/off sensitivity up to 20' away from the vehicle.  Always check the vehicle dashboard hybrid indicator to ensure the vehicle is truly "off" before any kind of work is performed on the vehicle.