Check this out:
http://abcnews.go.com/Blotter/loaded-gun-slips-past-tsa-screeners/story?id=12412458
Turns out that security fails to find guns and bomb parts at least 50% of the time. The results of random testing are so bad they are classified.
But perhaps this does not matter, as "security" is mostly about getting Americans to give up any right of privacy and funneling money to security agency corporate officers.
Joanna