In the last few years, I have noticed that Avis always delivers two keys with their rental cars. 
The keys are identical. They are attached to a tag and a remote by a fixed band that does not open. There is no way to separate the keys. If there are two drivers, they can’t each have one. Rental car keys are bulky enough, with the big tag and the remote. Two keys are so bulky, they don’t fit comfortably into pants pockets. They always get in the way.
I wonder what Avis is trying to do?
Of course, they want to keep the keys together, so when the car is eventually sold, they have both keys there. In the meantime they bother every one of their primary customers like me, car renters, and they hassle us with the keys.
In the event a renter should lose the key, he would lose both, of course; nothing saved there.
Wouldn’t it be much better to put the second key in a key warehouse indexed by the car’s VIN number? When the car is eventually sold, it can be mailed to the location of the car, and it’ll be a brand-new fresh key. If the first key is ever lost, the one in the warehouse would be a nice backup.
Other rental car companies don’t do this – as far as I can tell. It’s an Avis thing. And I don’t get it.