How do they define the location of a credit card? By the issuing bank or by the billing location? It is really not at all uncommon for these to be in different countries.

And as I said before, many credit card processing engines do not verify addresses for cards issued outside North America, so very often a dummy address in the desired country will suffice. (I haven't tried this with OWEs, but I have, for example, with iTunes which was, in principle, not available to people in Hong Kong. I have a UK (Jersey) based debit card - when I put the correct HK billing address it was rejected; when I put a dummy UK address against the same card it was accepted no problem.)