The gist of the Fourth Amendment, according to the Supreme Court, is "the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion." Which is why legal and privacy concerns are cropping up regarding the recent revelation that at least 50 US policing agencies have been discreetly using a radar technology that allows them to "see" motion inside homes, USA Today reports. Critics are worried about this extended surveillance, pointing out that search warrants are being flouted, clear rules for usage don't exist, and those using the radar aren't publicizing it. Law enforcement officials, however, claim the technology is needed to protect officers and that they're not advertising it because "if you disclose a technology or a method … you're telling the bad guys along with everyone else," an ex-supervisor for the US Marshals tells the paper.
The device most are using is the Range-R, a handheld sensor working as a "highly sensitive Doppler motion detector." The device sends out radio waves that penetrate walls—even concrete and brick, though not large metal objects—detecting movement up to 50 feet away on the other side; even people in bed breathing can be picked up by the sensor. Manufacturer L-3 Communications says it's sold about 200 of the devices to 50 agencies at $6,000 a pop. While it's true the sensors don't actually "see" anything other than a person's presence and any motion, the Supreme Court had this to say in 2001 in a case involving thermal-camera scanning. "[Rejected] is the Government’s contention that the thermal imaging was constitutional because it did not detect 'intimate details,'" read the ruling in Kyllo v. United States. "Such an approach would be wrong in principle because, in the sanctity of the home, all details are intimate details." (The NYPD, meanwhile, is using X-ray vans.)