Why would they ask you to leave? I am curious as to what you actually said and how you behaved. The rep could have been informed to not type in the card number and maybe they were new and did not realize they could imprint it. Maybe their group does not allow imprinting of the card on the contract. They do run the risk of a chargeback. I had something similar happen to me when I worked there. Some couple's card wouldn't go through at all and we were instructed that if that occurred to contact the card company. The couple got bitchy about it and just gave me another card. So, there's a good chance that they weren't trying to scam you into buying the coverage. Sacrificing the rental altogehter simply because you weren't taking damage waiver seems a little off to me.