But what it also seems to show us is that the modern interpretations and applications of pre-modern supersititions may be even less reliable.
One explanation for alien-shaped heads found in Mexico recently is that the human populations there were emulating alien visitors and that is why they bound their children's skulls. Talk of gods coming down from the sky of course reinforces these sorts of explanations.
This is a long shot, but it's not implausible. Intelligent life evolved here on Earth and we're now investigating life on other planets. It would be odd not to flip that scenario, at least as a possibility. It bugs me that this isn't considered a reasonable idea by a lot of people.
The problem, of course, is when we spin intricate stories around these plausibilities without any reason to. Perhaps with the passing of December 21st, 2012 (and maybe with announcements about microbial life on Mars at some point in the near future?) the alien talk will be a lot less unfounded, a lot less superstitutious, and considered a lot more reasonable.