metatron: " If you doubt that is true, take a look at the warning sight on the border of Area 51 :" use of deadly force authorized".
Have you considered the possibility that the government was driven to put up that sign to keep the nut jobs out? A simple keep-out sign was probably too subtle for them.
It's similar to the reason people put up "vicious dog" signs on their property even if they don't have a dog. It's to keep out those who insist on trying to get in, like the dubs.
"The plain consequence is (and it is a general maxim worthy of our attention), 'That no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish.'"
David Hume (1711-1776)