Originally Posted by G_Wolf

I noticed the screen for the x-ray machine faced a window. The TSA had apparently been concerned about security, and so had put up a big black sheet of plexiglass up against the window, so no one outside could see the screen.

The (unintended) side effect of doing that was that now the image on the screen was reflected and magnified on the plexiglass, and was clearly visible by the traveling public.