Originally Posted by IAHtraveler

While I don't particularly agree with many rental policies, the terms of the gas options are spelled out on Avis.com (listed under USA->Special Equipment->Fuel Options) and at every location I've been to for the last year or so, they have a sign somewhere indicating the fee if you return without a receipt while driving < 75 miles. It's also located in rental pamphlets or on your contract. So by agreeing to the rental from them, they have your authorization. The same as if you damage the car and return it unrepaired.