In what has to be one of their more ironic mess-ups, the TSA failed to seize box-cutters from a passenger which were then used to threaten other passengers.
I don’t actually see this so much as a commentary on how incompetent the TSA is, but rather as testimony to how pre-screening against a very unlikely event such as the 2001 terrorists attacks is statistically doomed to failure. The prior odds of such an event are so very low than no current feasible test can work. The sensitivity and specificity are just not high enough. This event as well as the TSAs own tests showing 97% of attempts to smuggle prohibited items making it through demonstrate too low a sensitivity.