Your lucky, at least they tell you.

Last week in Cleveland I get there (with an Exec Elite reservation) and there are about 10 people in line outside waiting for the next available car to roll up. Not just Emerald aisle, but everyone. Took about 25 minutes to finally get your choice, take it or leave it.

I told the Manager, you know how to take a reservation, you just don't know how to hold it (stolen from the Seinfeld episode).

Avis wasn't taking walk-ups at that point (although they had cars on the lot), so I had to wait.