The Reason Public Policy Institute has just issued a report charging the TSA with operating a "fallacious" airport security policy that treats all passengers and baggage as if they posed an "equal" threat to aviation security. It also charges that using this approach it has made Airports less secure as it spends too much time and resources on people who are no threat and too little on the few that might be.
It is an interesting report and I believe really hightlights the serious problems with the way the TSA run Airport security.
It can be found at
http://www.rppi.org/ps308.pdf. It is rather long but worth reading.