&gt;&gt; There should be no reason for us to go through a body scanner if the TSA and DHS believe their background check and fingerprinting are effective.<p>The general concept of security in layers is perfectly reasonable because no measure can be 100% effective. Combining a few 99% effective measures can get you acceptably close. We do the same thing in cybersecurity.<p>That said, the TSA is still dumb because of how arbitrary and unfair the requirements can be.