I sure wouldn't belittle librarians around here, man. You'll get your knuckles whacked with a ruler.

Actually, I'd cite the library record checks as one of the many evils of the "Patriot" Act; along with carte blanche for federal bureaucrats to read our credit reports and bank records and credit card statements and tax returns and video rental records and Internet service logs and phone records...all at the invocation of the magic word "terrorism". I can almost hear that cheezy WWII movie cliche: "Und so, iff you haff notting to hide, vhy ah you so vorried about zeez 'civil liberties', hmmmm?"

Does an American need a reason to object to government fishing expeditions and random surveillance?

Then there's the existence of secret provisions in the "Patriot" Act. Doesn't that just boggle your mind? Is ignorance of the law now an excuse? Unlikely. But what would you do if a Fed hauled you off on the grounds that you've violated one of those secret laws? How would you know that the law even exists? How could you defend yourself against the charge that you've violated a law you don't have the security clearance to read? And what might those secret laws be? Well, we can't know directly, because under the "Patriot" Act the law is whatever the government says it is; but think about it: The only laws that would need to be kept secret are those that grant the government illegitimate power--power that would prohibited by the Constitution. The "Patriot" Act is by its very nature an attack on the Constitution.

All of the above being techniques traditionally used by dictatorships to keep the population in its place, shall we retroactively absolve the Soviet Union and Nazi Germany because now we claim necessity too? Or can we, for once, be honest about the Faustian bargain we're making as we trade our liberty for physical security? We are giving up essential American core values; the only honest discussion we can have is just how much of America we'll sacrifice to achieve security. "We have to destroy the country in order to save it" they said back then about Vietnam. Now it's America we're talking about destroying in order to save it. We have a right to some say in the matter.

So, for that matter, does Ben Franklin: "Those who would trade liberty for security deserve neither".

The "Patriot" Act's kind of off the topic you brought up originally. Sorry about that. Your model for security screening's not unworkable; I was just trying to make the general point that any time you have a particular set of criteria you screen for, you become predictable, and you give your enemy a chance to figure out another way. Even weighting the odds like you describe doesn't really help if your enemy knows your "algorithm" and weighting factors. Every algorithm has a counteralgorithm. You actually seemed to be going for a blend of randomness with directed searching when you talk about searching only 20% of, say, the buxom blondes (and dude, I'm surprised at you, only 20%?). Adding some randomness probably strengthens the system overall.

Maybe I'm thinking like an engineer, one who occasionally has to build secure systems. The best thing I can do is prevent an attacker from learning anything about my defenses. If the attacker has no info about where and how to attack, he's likely to attack at random, and likely to run into one of my defenses. Stacks the deck in my favor. Bring 'em on...