It looks like they are working to erode searches again, using dogs to detect drugs inside a home. http://www.scotusblog.com/2012/10/argument-preview-drug-snif...
Everything I learned in high school civics class seems to be obsolete when it comes to our Constitutional rights: "bong hits for jesus", "administrative" searches (body scanners), and now street searches.
Why is it the argument from ignorance/lack of imagination via fear is so compelling? "We need to do X to stop Y." Where Y is something very remote but really scary.
What an asshole.
[1]: http://en.wikipedia.org/wiki/School_speech_(First_Amendment)
Just curious ... when you fly, do you get hassled or barred from the plane?
TSA scanners on the other hand... ;)
[1] https://en.wikipedia.org/wiki/Infrared (300 GHz to 430 THz)
(I'm sympathetic to your goals here, but I think the tough questions need to be asked. They certainly will be in court.)
These particular sensors might indeed be passive, but it would limit their range and SNR. Be wary of manufacturers simply selling the emitter as a second SKU to garner the label passive on their detectors.
[1] I work at a company making SWIR/MWIR imagers.
The distinction you're trying to make is between ionizing radiation (x-rays; causes cancer) and non-ionizing radiation (all other sorts of electromagnetic radiation including visible light, infrared, microwaves, and so on; doesn't cause cancer).
The TSA currently has some scanners that scan using x-rays and some that scan with non-ionizing radiation.
A regular boring old security camera is also a scanner that emits non-ionizing radiation - most of them use infrared LEDs to illuminate at night. If you could see into the infrared it would look like every security camera has a big flashlight mounted next to it, shining on you. So the target, you, gets irradiated with non-ionizing infrared rays, which bounce back to the camera and are recorded. Using different wavelengths of illumination, you find that some of them penetrate clothes easily to see what's underneath. That's what the NYPD/security apparatus are interested in.
I'm not defending the scanners (obviously)... I just want the case against them to be clear and sound.