I encountered the same 7/9 - 8/20 period black out at a local non-airport location that I frequent when trying to use an AF two free weekend award. First I had heard that this is nationwide thing.

First, an AF CSR said that she could do the following: I would have to pay the full amount at the local Avis location. She would see that my credit card was reimbursed for the two free days, a couple days later. I declined for two reasons. First, what proof or assurance did I have that the credit would come through? Second, she was only crediting the day rate and not the tax portion of the rental. They believe that's how it's supposed to work, but I never pay the percentage based taxes/fees on a free day rental -- only if there is a daily fee and they are usually modest -- $2-4.

So I talked to a very accommodating, on-the-ball person at the location (that has been most helpful in the past) and I was assured that a car was being held for me and that the Free Weekend code would be entered when I made the rental (she works that day). Once the coupon code was in the contract, I was assured it would not be a problem.

Moral of the story is that if you are renting at a known location and you know one of the agents well, give them a call. Won't help everybody, but some...

Now, I have to figure out some nice little gift/gratuity for her assistance.