Ed Felton posts an annecdote that perfectly captures the absurdity of the Security Theater we all endure at airports.
I read once that if everyone has to go to the airport an hour earlier than they used to, the nation annually loses productivity equal to the amount of destruction that the 9/11 bombing cost. A little googling suggests that the number may be as low as half a World Trade Center bombing per year. [One estimate suggests that the annual value of time lost by business and leisure travelers because of airport delays in 1999 was $11.8 billion, while a different (2001) estimate put the cost of the of the WTC clearnup and reconstruction at $23 billion.] Even half a WTC per year is handing terrorists a major, continuing victory. Spending the money on useless show is handing terrorists a giant, continuing victory.
I call it the Bush tax.