Most gov't agencies refuse to allow anyone to have any real knowledge of UFOs. The only reason they allow people to talk about them at all, is b/c most people don't take them seriously. They make up any story they can to disprove most of the sightings, and terrorize eye witnesses into keeping what they saw to themselves. Even when the Roswell crash happened in Mexico, and people actually saw the space craft, and possibly the aliens themselves, the gov't was able to pretty much cover up the entire thing. I can't remember what their excuse was, possibly something involving a weather balloon or something... I don't know.