Originally Posted by MeNoSay
Where does this happen? I've traveled some (although not as much as many here) -- around 20 different countries and never seen this come up.
Saw it twice in Switzerland in Jun. Both times at a hotel restaurant. The second time despite my (to me) clear instructions that it be run in CHF.
How do they know that you're an American?
Assuming your question is serious -
(a) The issuing bank is identified on the card, obviously.
(b) For all I know there may be a feature in the card machine to charge in the currency of the issuing bank (conveniently plussing-up the exchange rate while doing so).