Security: balancing cost against value:

Bruce Schneier, in his weblogs and books, is eloquent and clear on this subject: all security procedures are a tradeoff of cost against value. No procedures are perfect, and we have a finite amount of money to spend on security. It's unfortunate that security laws and materials are usually adopted on emotional grounds, or because they clearly look useful, without any consideration of balancing cost. Here's a wonderful example, by Beverly Wang (associated Press writer), reported in boston.com news:
CONCORD, N.H. --Forcing people to show passports or national ID cards at Canadian border crossings is an inconvenient, money-wasting invasion of privacy that won't protect against terrorism, according to one Democrat running in the 1st Congressional District.

"Surely a terrorist could figure out how to walk through the woods to avoid the border guards," said Carol Shea-Porter of Rochester. "The program would cost billions of dollars to implement, inconvenience millions of honest people, and would only create the illusion of safety."