Even the leader of the free world sometimes has his credit card declined. As Obama explained today while signing an executive order protecting consumers from identity theft, he was at a New York restaurant during the UN general assembly when "my credit card was rejected," he said. "It turned out I guess I don’t use it enough. They were—they thought there was some fraud going on. Fortunately, Michelle had hers. I was trying to explain to the waitress, you know, I really think that I’ve been paying my bills."
As the Washington Post reports, Obama was also concerned about one of his credit cards back in July, when he ordered more than $300 worth of food in Austin only to discover he didn't have enough cash. He paid with a credit card—successfully—but first checked with the trip director, who assured him the card would work. (On the other hand, when Joe Biden was short on cash for food, he just borrowed $10 from an aide.)