There is no incentive to send a car back. Some try to send cars back with one-ways but there is no need to do so. They used to require them to go back years ago but not anymore. The only time you would need to get a car back is if you are dealing with a licensee vehicle. There are a few employees that believe that you aren't supposed to let a local leave but they are incorrect. When I had to switch out a car once at ATL the security agent told me that I should have found a car from my city and I politely explained that it didn't matter and I'm not going to search through 5000 cars to see if 1 of the 300 cars that my small market has is available (I was an employee with car privileges so this was a non-rev movement so she took the opportunity to be a pain).

Locations cannot demand that a car be sent back to them. However, Corvettes are not supposed to leave their owning city and are not eligible for one-way rentals. So, if one did end up somewhere it wasn't supposed to then it would need to be sent back. In that particular situation, it is possible that a decision may be made to send it with a customer on a one-way if such a reservation exists. However, normally, if you are going one-way, you have a midsize reservation to DEN, you are going to get the Mazda 6 rather than the G35 from Colorado.