I had a bad experience with Emerald Club, and will not use them again. 2 yrs ago when we checked our car in, we were charged for 1/4 tank of gas.....or something like that. When I asked the gentleman why, explained that he had a gauge that told him how much gas was in the tank. WHAT? Show me, I don't think so. He continued to argue, even after I showed him my receipt from the gas station (last exit before the airport) I had a wonderful trip and was headed home.....I did not have time to argue. As soon as I got home, I called and spoke to a Customer Service Rep that tried telling me the same thing, I asked immediately to speak to a supervisor. The supervisor apologized for the entire situation, assured me I'd have a credit back on my card, and told me they are not sure why I was told this they had no such device. Duh! I simply thanked the supervisor and explained to him that they could cancel my EC membership effective immediately. That while I appreciate everything he had done I would not choose to use National ever again because I should not have to go through all this just to make sure I'm not charged for something I shouldn't be charged for.