They do. All 5 major CC issuers have links to their full merchant agreements somewhere on their sites.
Amex:
https://www152.americanexpress.com/E...ernet&origin=6
MC:
http://www.mastercard.com/us/persona...iolations.html
Go to the sites for Visa, Diners and Discover for the others and you'll find them.
BTW, it was mentioned by a newbie in this thread that car dealers most likely are using they're non-exceptance of CCs for full payment of the vehicle as a negoitiation tactic, and nothing more. That is not true. Many genuinely don't want to except the CC simply because they will lose money processing the payment.
The newbie (Robin something, I believe), also suggested that CC companies really wont do anything when it actually comes down to the situation between the merchant and the CC company. That it also simply not true. The links above, as well as many people's personal experience (including my own) attest to the fact that CC companies stand by their merchant agreements quite vigorously.
Point, in fact, I pressed a dealer recently to accept my Amex for full purchase price for my SUV ($45,000 full), and they refused. They do accept Amex for servicing, but not for sales. I called Amex on the spot and handed the phone to the sales rep who disappeared. He came back and said his finance manager wouldn't accept talking to Amex over my cell phone. I told this to the Amex CSR and they called him directly while I was still there. I waited an hour, and then he came out and extremely reluctantly accepted my Amex for full payment. You see, Robin, Amex threatened to pull their contract with the dealer for merchant agreement violation, because they DO NOT have any legal standing to refuse payment for one purchase and choose to accept it for another - nor do they have the right limit the amount of payment on the accepted method of payment. And the dealer does not want to lose the ability to accept Amex for all of the charges it takes.
So it is not a fallacy, the merchant agreements exist for our benefit as well. In the end, you will find some dealers will not care and will stand by their own policy, but that is when you file a complaint through one of the links above and follow up with YOUR CC company. Nearly every time I have done this, the merchant backs down.