Whether any of these claims are true or not, many will believe them...using the common weird logic of: If we don't have 'evidence', it must be because they are hiding the evidence! I'm not sure why 'don't have evidence' doesn't more often indicate there might not BE any evidence.
(remember the 100MPG carburetor? We don't have it because the oil companies are hiding it!)

*I* would love to be a fly on the wall when new presidents are briefed (or sandbagged) about Area 51 & related issues. I do have some concern that some matters are kept from even the president.