I agree with most of the points in this article, but saying that all people who forge boarding passes will use latex gloves seems false.<p>From my point of view the point of multiple screenings is to increase the difficulty and complexity of pulling off a particular attack. Sure, individually you can think of a way to counter each one, but as you add constraints you reduce the pool of people willing and able to pull it off. (So now you need a person who wants to cause terror, who is willing to blow themselves up, who can forge simple documents, who remembered to wear latex gloves, who can act cool enough to avoid extra screenings when walking past guards with machine guns, etc, etc, etc). Sure some eliminate more than others, but you multiply enough .95s together and you get a small number.