This scanner is something every passenger would walk through.
The example I heard used recently is that it's not that difficult for someone to hide a quantity of explosives on themselves without them being visible under their clothes.
They might be discovered if every passenger was patted down, but are hard to detect by just looking at the person, and you don't need metallic items that would set off a metal detector to make a bomb.
However, a scanner that generally shows what is hidden under their clothes makes finding such items likely rather than unlikely.
My point remanins - do you think any of the scanners would figure out that, say, an ace bandage wrapped around an elbow is made of explosive material ? Or how about explosives disguised as a corset ? Underwire bras ? Look at the liquid explosives plot - do you think the TSA screeners would catch any of that ? If you do you have a higher notion of their intelligence than I do.
I flew from San Diego to Phila last year with a male friend. We were pulled aside to have our bags checked out for further scrutiny - 2 middle-aged WASPs. Our bags were checked in San Diego by a man who barely spoke English. The man spent 2 minutes on my friend's bag. When he checked my bag he held up my underwear to the light to look at them, ran them thru his hands a few times, felt up my bras and other underwear, and ignored obvious items like a hair dryer and an electric toothbrush. He spent over 10 minutes on my bag, dropped some of my stuff on the floor, and made a mess of everything - all in full sight of the public passing by. I complained to an airport security supervisor that the guy must have been trained at Victoria's Secret - I certainly felt the guy was getting his jollies on fondling my underwear.
Get the picture ? Pretty soon they'll just have us leave our clothes in our checked baggage and fly nude. We are no safer with any of this crap - we need profiling like El Al does.