In my experience, I've never had a successful credit card chargeback with AVIS. They are very good with proving to credit card companies what is in their T&C's.

The two times I did it, AMEX always tried the dispute, and AVIS faxed their paperwork within days, and I got a complete copy and the dispute was overruled.

IMHO, too often on this board, people just say, "dispute it" when its not a policy concern -- its that someone just doesnt like what the rental agency is doing to them. They dont think its "Fair" despite signing a ridiculously long document that basically waives any and all of their rights.

Just because you dont think its fair, doesnt entitle you to dispute credit card charges that you agreed to in writing or in contract.