I think when WBC was getting all up in arms about Comic Con, somebody said that, judging by the kind of media and following we have for fictional characters, it is possible that some alien or far future civilization could mistake them for our gods, but that the unfortunate implications of this are that the stories and characters we've been worshipping for a thousand years or two might have been just that - stories and characters.
It may have been about that time I read an expanded universe Doctor Who novel called Night of the Humans, in which a primitive human civilization, decended from the passangers of a crashed cargo ship, worship the shipping company's mascot Bozo, and believe that some old Western films that were in the ship are the stories of Bozo's sons, brothers, and the minions of 'the evil one'. It's also pretty clear by the end of the book that they welcome death via meteor as they think it must be Bozo coming to take them to 'El Paso', their idea of heaven. It's a bit of a disturbing thought, and sums up why I don't feel I want to trust my whole life to religion - there's every probability that it's just a story.