I guess this is the reverse of your story. I was at IAD back in August and was at one of the kiosks. The woman next to me had her email receipt and was fumbling with the kiosk and couldn't get it to print a boarding pass. I glance over and notice she's leaving out of BWI in less than 2 hours. I tell her she's at the wrong airport, and she's so confused.

I have to wonder what she ended up doing because there was a cancellation so I doubt that she was able to get in a flight out of Dulles. At least in this situation, it showed that the kiosks don't print out passes for other airports, because I wonder what the tsa would do. (Though online printed boarding passes could still be taken to the wrong airport)