I'm a former Zipcar employee. There are some interesting things about Zipcars, one being that if the car can't get a phone signal, it will allow any Zipcard to

I'm a former Zipcar employee. There are some interesting things about Zipcars, one being that if the car can't get a phone signal, it will allow any Zipcard to unlock it (since the car can't know for sure if that card has a reservation). Also, in the UK, there were instances of the more expensive cars being taken to garages and having some parts swapped out for cheaper parts and sold on the black market.