Not new, although normally you should be able to get it refunded without too much trouble.
http://www.flyertalk.com/forum/avis-...ee-policy.html
In some sense I can actually see the logic behind this. Avis are trying to manage inventory. If you said you were going to return the car at midday, then they potentially have planned to have it back in the pool for rental again by (say) 4pm. If you don't return it until 8pm, then they could be out of cars for the next renter. Of course, one renter doing that likely isn't going to be a problem, but with multiple it could be.
Booking all rentals as full 24 hour multiples doesn't help with their inventory, but at least they can plan based on that...