Backscatters are useless
 

Scientific article about backscatter technology (and it's shortcomings). Ouch, TSA, really... found first on slashdot.

http://tech.slashdot.org/story/10/12...-Easily-Fooled

Juicy quote:

Pfft, thats easy to fix...

WTMD, Scanner and Full body Pat Down - every passenger, every time.

And the pancake of PETN?

Anything placed at the bottom of your feet would be undetectable.

Did the government put these machines through a complete test to determine if they were effective against an enemy that is "clever and ever evolving"?

We don't even know for sure if it would have caught the underwear bomber.

I believe that there are many ways to defeat the machine. It is too late now for the government to back down and admit error. So in true government fashion, charge forward and worry about things later.

I could see an enterprising and compensating tewwowist "padding their junk" with stuff that would show up as if they were particularly well-endowed on the scanner. Then again, that might just invite a grope or two :D

One (compound) word: buttbomb.

Oh, and was it a 5 year old blond girl who was the delivery mechanism for the buttbomb? Was it a grandmother from Cedar Rapids, Iowa? Rhetorical questions. :rolleyes:

Oh, they're quite great at singling out disabled people, women who have the audacity to bleed into a pad rather than an internal "sanitary product", and anyone else with a non-TSA-approved body, which seems to change on a daily basis but let's just say it definitely reflects the mindset of the people the TSA hires.

So, yes, they have a use. They keep people like me off planes, since the TSA has no policy other than "do whatever the hell we want to you, and we don't care about your dignity, keeping your carry-on baggage from getting stolen, or actual security." Security theatre costs money to the taxpayer and the airlines, it hurts whomever the TSA decides should be harassed (and oftentimes these are people who have specifically enumerated legal rights, but it's not like the TSA cares...and even people who don't have such rights deserve dignity and to be able to fly), and it lends itself to people thinking they're safe when they're not. Costs, hurts, lies. That's what the TSA is all about.

Analogy time.

It appears the current American security is similar to car alarms. You can't stop the car thief, all you can do is make it hard enough to make the thief want to go to the next car. Yet you're not going to prevent the knowledgeable, skilled, and motivated thief, they will get your car, one way or the other. You just put up enough challenges to the thief that they go somewhere else to steal. Or you own a car that doesn't provide anything they want. Or you accept your car will be stolen, and make appropriate plans.

Sometimes, you'd think this mode isn't to stop or catch the aggressor, it's to scare them away.

Ahh car alarms, once people paid attention to them. Now people don't pay them one bit of attention.
Sound familiar? blah blah blah condition orange blah blah

Exactly.

I was traveling out of an airport in CA once, probably sometime around mid-2002. I was sitting next to a man and woman (age 60ish) vacationing from the UK. This was of course, during the early part of all the security hype and we were getting constantly bombarded with messages about unattended bags.

Well, being a relatively honest (perhaps somewhat naive) kid at the time I asked the lady if she would mind keeping an eye on my bag while I ran to the rest room. She answered me with "Well, I don't think I'm supposed to do that since they're telling us that no bags should be left unattended." Fast-forward 8 years and now you'll get "Sure buddy, in fact when you get back I gotta go too, that OK?"

*I'm not faulting the woman for doing what she thought was safe at the time. I'm just pointing out that when you overuse a threat it eventually becomes something that gets ignored. The same logic is used by weather offices on the Plains during tornado season. You would be surprised how much consideration is taken internally when making the decision to issue a "tornado warning" to the public. One has to be wise - if you overuse the tool, eventually deaths will result when people no longer take you seriously.

I am not an expert in backscatter x-ray physics, but I am knowledgeable scientist in the business of evaluating the scientific literature of a number of subjects related to, but not directly in this field, and this article has alarm bells going off right from the start:

1. Authors: One emeritus, one not associated with an academic or recognized lab. The first author published years ago in MRI but is not now an active researcher in backscatter x-ray physics.

2. Image source: Published public images.

3. Method: monte carlo simulation with no direct measurement of exposure, no actual testing of subjects with simulated explosives or contraband, no new data other than simulation output, i.e. GIGO;

4. References: Literature references on the model, a couple of very old books, a recent letter to the editor by the lead author. No auto-cites of relevant papers describing basic research by either author.

This is an incredibly weak paper by someone who ran a series of simulations. While I think the debate over safety and efficacy of these devices is important, this paper is not the one to trot out to prove your case. This is a perfect example of what science is not.

Speculation at best. I would bet on the machine, and I operate one.

Agree that the paper is weak, as are most papers when the actual subject of the investigation is not available. If you have access to a Rapiscan, I can arrange measurements by experts.

They would have a hard time doing better without access to the real machines--something they certainly won't get. If the report is false it would be easy enough to rebut--the TSA could publish images showing what the explosive pancakes really looked like.

I agree it is weak science. Unfortunately, there is no good science regarding these machines.