Engineer Jonathan Corbett, who runs the blog TSA Out of Our Pants, says the flaw exists because the scanner uses dark colors to highlight potential threats like weapons or explosives. Yet, the scanner also uses a dark background, as seen in the image above.
He explained, “Again that’s light figure, black background, and BLACK threat items. Yes that’s right, if you have a metallic object on your side, it will be the same color as the background and therefore completely invisible to both visual and automated inspection.”
If you think about it, it makes sense. IF the object was side-on to the scanner, and on your side, you can imagine, looking at the image above, that it would be "invisible." Corbett said he was able to sneak a metal carrying case through Fort Lauderdale-Hollywood International Airport and Cleveland-Hopkins International Airport.
It does smake sense BUT it's also true that the TSA has been replacing the original and oft-criticized full body scanners with new ones that not only don't depict a person's body in such graphic fashion, but don't use a black background, either (below)
Watch Corbett's video, below.