No offense taken; I too do not trust US law enforcement to use this technology in a manner that respects the privacy and rights of law-abiding citizens.

Nonetheless, it is a fact that this technology has been used to trace the location of people responsible for the placement of roadside bombs in warzones abroad, and has been used to locate the headquarters of an organized crime group in Juarez, Mexico, a place that averaged 8.5 killings per day in 2010.

I highly recommend listening to the Radiolab story, it raises some interesting points.