The mechanical backup is only good for the door isn't it? Does it also start the car because I dont see anywhere to put the key. If not, then I don't see too much harm in a well placed hide a key. I think it would be worth the price of admission just so I don't have to worry about accidentally hitting the panic button when I'm trying to open the trunk. Not worrying about sitting on the key fob and unlocking my car would be great too