Suppose I wore a fat and long prothesis on my schlong and went through airport security with it? As it would be rubber or some other non-metal, I don't think it would set off anything. But, the full-body scanner would certainly pick it up. Then what? Do I then get an enhanced pat-down with some guy's hand examining the monster rod? And would I be subject to further search? Then, once determined that it's a fake addition to my regular-sized member, have I broken any laws?
This is all speculation, mind you. I don't have any real plans of doing this. I just think it would be funny trying to gauge the inspector's reaction to such a "discovery".