Phil,
Ha ha! The same thing happened to me in Frankfurt. I arrived by ICE train from Munich, jumped into a taxi and asked for the Hotel Monopol. The driver started screaming and pulling out his hair (really!) He said it was on the other side of the train station but since he already drove out of the taxi stand, he had to take me and would have to go back and wait in the long taxi queue again. I told him I felt really bad and gave him something like a 300% tip.