Originally Posted by
jmastron
I believe in most cars the emergency key part itself won't start the car (if pushbutton start there may not even be a starter keyhole). The "dead fob battery" failsafe for the door locks is the physical key, but the failsafe for the starter is a secondary passive NFC (no self-power needed) in the fob that you hold up to the dash while pressing the button.
Yeah, on some fobs it's too easy to inadvertently release the otherwise-loose fob from the emergency key part that's attached to the keyring.
EDIT: I may be wrong about that -- some searches show that VWs at least have the passive NFC chip in the emergency key part (so you can give that to a valet). You'd have to know to hold that up to the right place, of course.
Actually, you were correct. For cars that have an actual ignition slot where you can insert the key, you can start it, but the VW Atlas isn't one of those, so without the fob, you can only get into the car, but not start it.
To answer the OP's original question, they will usually charge the credit card used for the rental (assuming the charge goes through). The tow is likely to be expensive. I'd say that worst-case, you're probably looking at around $1K but it's possible you'll get away with less. Please do report back on the final outcome as it helps others in similar situations to know what to expect. Good luck!