Not having the power on is a pain. At work my cell phone was complaining about low power. I put the car in ACC mode and let it charge for an hour. Walking away with the key didn't take it out of ACC mode. I don't know if someone could have walked up and start the car, but I work on a navy base in a small building with my car right outside my window so I wasn't worried. Obviously I wouldn't recommend this in a big city.