Just The Tip Of The Iceberg
I had a chance to try out a similar device. There were problems with noise and false positives. Wearing it around the house I got a lot of false positives after my mom had gone to bed and my dad got ready to call it a night. I seemed to get threat readings even from the near subliminal sounds he made. It was quite distracting. She's much too good for him. Also, outdoors, flamboyantly dressed men displaying dramatic body language seemed to push threat reaction into the red zone.
A schism erupted between specific threats and more general, almost, archetypal threats. Generally I found if I just forcefully asserted my will most of the threats seem to disappear.
Of course with the DARPA stuff there are protocol issues when the soldiers network and the stuff seems not to scale well.