So I get the fact that elites can always book a car with 24 hours notice, but what happens when a location is oversold and they have no cars available, despite the fact that you have a reservation (ala Seinfeld)? This has happened to me a couple of times in the past two years, such that I never pick up a week-end car at my downtown location on a Friday night anymore. Do they make sure that they always have a car set aside for elite reservations?
That's a good question. I think at a big enough airport there will always be enough one-way drops and early returns to rarely bottom out. I don't know National's official policy but I imagine they try to keep it as close to but not at zero availability as they can.
For smaller locations, I know the one time I used my elite status for a booking was in Banff, Alberta last year. We needed a car to get all our stuff back to Calgary and all the rental outlets were long sold out (right in between Christmas and New Year's). I got a fullsize at my regular corporate rate and got a Magnum AWD that was tagged from Calgary. So there's potential that the car was brought in specifically for my booking.