Anyone ever had these things read a positive on their stuff, or seen it happen to someone else?

I'm really curious to see what would happen, and how often it happens -- whether they're some big flashing red light and a presumption of guilt, or whether it's just a close inspection of your stuff. I imagine there are folks who work with compounds similar to those in plastic explosives, whose luggage carries the matching "signatures."

Some links to look at:

http://www.business2.com/articles/ma...,17513,FF.html (basics of ion mobility spectrometry)

http://www.nashintl.com/k9.html (dogs can sniff for bombs too)

http://www.sandia.gov/LabNews/LN08-1...fer_story.html (portable electronic sniffing dog)