The predicament described by McGrath almost happened to me, too, but in my case, my wallet really was stolen. It almost seemed we were stranded in a foreign country with no source of money. Then we remembered my wife was carrying a bank card that I didn't have, and therefore didn't need to cancel. It was the account she normally uses only for her music-related income and expenses. We were able to call our bank and have them transfer enough money into that account so we could finish our trip.

From now on, when we travel, we will make a point of carrying cards on different accounts. If the cards are on one account, you can't cancel one card without canceling them both.