[dalke]

It's more "all people who forge boarding passes with the intent of using the plane as part of a terroristic plot will use latex gloves if they also have a bomb."

The point was that multiple layers are only useful if they test different thing. I'm more inclined to believe that those two layers are "tantamount to performing the same test twice" because they can both be done before the fact, and planned for.

The problem about multiplying enough 0.95s together is the number of false positives that occur. The article mentions one, where an air marshal killed a deranged passenger in Miami. That's an extreme case. Hidden is the, what, 5 minutes needed for screening * 700 million passengers per year giving over 6,000 extra person-years wasted waiting on security every year.