All car sharing platforms* I have used in Amsterdam/The Netherlands/Europe have a key in the glove compartment that you can take out when you park the car. Why doesn't Zipcar do the same?
* i.e. Car2Go, ConnectCar, MyWheels, Fetch, SnappCar
* i.e. Car2Go, ConnectCar, MyWheels, Fetch, SnappCar
I'm reminded of European hotels that want you to leave the room key at the front desk.
On the other hand, the fuel payment card does missing - but at least Zipcar in the UK are efficient at refunding your own payment when provided with a receipt.