While I agree that this is the way Avis has chosen to manage the fleet, I'm not sure that it's correct for CVG (in particular). Regardless of the time, date, month, CVG would consistantly decline any and all one-way rentals. May have changed, it's been a long time. At the same time, the other two 'major' rental agencies gladly gave one-way rentals.

If it happened once or twice, fine, that's scheduling. When it happens in dozens (literally) of attempts, then there's something else going on. I heard - second hand - that the policy was implemented to keep people from driving cars to "cheaper" airfare markets, and leaving them (in that scenario, the traveler needs to get home somehow... logically, you'd think they rent a car). No conspiracy involved.

For me, the solution was to use Hertz or National. YMMV.