Via Bruce Schneier, a retired counter-terrorism expert rants about the TSA's airport screenings:
The entire TSA paradigm is flawed. It requires an impossibility for it to succeed. For the TSA model to work, every single possible means of causing danger to an aircraft or its passengers must be eliminated. This is an impossibility. While passengers are being frisked and digitally strip-searched a few dozen yards away, cooks and dish washers at the local concourse “Chili’s” are using and cleaning butcher knives.
TSA’s de facto policy to this point has been to react to the latest thing tried by a terrorist, which is invariably something that Al Qaeda identified as a technique not addressed by current screening. While this narrows Al Qaeda’s options, their list of attack ideas remains long and they are imaginative. Therefore, if TSA continues to react to each and every new thing tried, three things are certain:
1. Nothing Al Qaeda tries will be caught the first time because it was designed around gaps in TSA security.
2. It is impossible to eliminate all gaps in airline security.
3. Airline security screening based on eliminating every vulnerability will therefore fail because it is impossible. But it will by necessity become increasingly onerous and invasive on the travelers.
Nothing new in the critique, but it's good to hear it from someone who knows his stuff.