I understand the political purpose, but what is the security purpose of random selection? I mean, this is all to keep us safe, right?

Randomness in security systems add unpredictability. in the case of WTMDs, you might plan on taking a ceramic knife through the portal, knowing that it contains no metal and won't set off the alarm. Since the portal has a "randomizer", however, you still can't be sure you won't get a pat-down, and the knife is found, and you're in trouble.

Just one example.

-SB-

You "could" be next to get select. Depending on the circumstances, this will deter either no or most people intent on doing something.

Well, that's the first time I've ever been "randomly" selected by the WTMD, and I travel on average 3 days week for the last six years...

As we've heard many tales of perceived improperly selected random pat-downs by TSOs, this might be using an already existing capability of that WTMD that wasn't previously widely used. Rather then having a human define randomness, now any random pat-down selectee can be told that the WTMD picked them, and not a person.

So that would make it... random? I take it you're not the only passenger flying out of whatever airport you're departing from? It actually does make sense.

-SB-

Random selection is the opposite of thinking. It can be done in a couple of lines of programming in any modern language. You want 3% of all passengers to receive a random patdown? Generate a random number, x, between 1 and 100. If x is less than or equal to 3, blink the yellow light.

I've been through customs in Mexico, and everyone has to push a button. If you get a green light, you go through, a red light gets additional hand-searching. I've seen a thirty-year old man with a 70-lb suitcase patiently holding the hand of a 3-year old as her tiny backpack is searched. Totally random, and it may not make sense from a 'logical target' perspective, but if you wanted to sneak in something illegal, why not put it in the 3-year old's bag?

+1 - As long as there truly is a randomizer and not an excuse for a non-random selection by a TSO.

If 3% of passengers need to be hand-searched to generate uncertainty, (arguable, I know) I would rather have 3 randomly chosen, rather than 3 chosen by a TSO. The TSO might profile by choosing only dark-skinned young men. (Whether or not this is acceptable/desirable is up to your personal ethics.) Or they might choose targets that are unlikely to protest, like young mothers with children or elderly people. Or the TSO might randomly choose "cuties" and "hotties". I've heard reports of all three.

Sorry, my question was more rhetorical. As FFs know better than anyone, there is very little that is "random" about American airport security. There is, however, a surface-level illusion of being random.

In statistics, true randomness causes clusters. However, most people have the perception that random is "evenly spaced out" which is decidedly NOT random.

I would be OK with an extra security measure for those small numbers of people who are truly randomly selected by machine. (Like in Mexico). However, this extra screen must still NOT include groping or NOS. It should be a random bag check or a random swab. Something of that nature.

About as variable as a random selection?

Oh good grief, are we have to the ceramic knife nonsense? The biggest threat to an aircraft is not the ceramic knife or any other non-metallic primary attack weapon. It is explosives, which, incidentally, the NoS can't detect when carried by a well trained person.

Pull a knife on a plane and you likely won't ever live to see the outside of said plane. People aren't going to let you do whatever you want. And the cockpit doors are hardened so what exactly would be the purpose? You scare some passengers and end up with multiple fractures (and still alive if you are really lucky).

The answer to the whole security theater is to focus on finding explosives. The TSA removed the mechanical means when they threw away the puffer machines. The living means of detection is waiting for service at dog pounds across the country.

And there are fake "I can predict what you guessed" tricks based on that.

For 'true' randomness, let the passenger (or person with a gate pass), roll a 6 sided dice selected from a set. Roll a 1, get selected for secondary. Since the PAX does the randomization, the heat is off the TSA for how they got selected, assuming non-loaded dice. It'd probably reduce some of the CP stress giving the PAX a sense of control over the situation.

If 1 in 6 isn't suitable, there's other-sided dice available, but the classic cube is most familiar with all. A pair of them with other numbers selected can sit in too.

With this system, the means of selection is 100% transparent, no SSI, and yet nobody can predict the result, so it's truly random, as opposed to being capricious and arbitrary.

This may be more (or less) poplar in LAS or ACJ, depending on how you did at the tables...

Is it random, or is it "random"?

http://www.liveleak.com/view?i=118_1290452447

Could there be some TSO sitting in the background who pushes a button every-time an attractive female goes through the WTMD?