Ars Technica: “…Functioning like Google Maps, Fog Reveal is marketed to police departments as a cheap way to harvest data from 250 million devices in the US. For several thousand dollars annually, the software lets police trace unique borders around large, customized regions to generate a list of devices in the area. Police can use Fog Reveal to geofence entire buildings or street blocks—like the area surrounding an abortion clinic—and get information on devices used within and surrounding those buildings to identify suspects. On top of identifying devices used in a targeted location, Fog Reveal also can be used to search by device and see everywhere that device has been used. That means cops could identify devices at a clinic and then follow them home to identify the person connected to that device. Or they could identify a device and follow it to an abortion clinic. The EFF discovered that Fog Reveal is already covertly used by police in various states, sometimes to conduct warrantless searches. Police demonstrating interest in the tool shows how all those smaller, less-scrutinized apps that sell user data to third parties could end up collectively contributing more data to local and state police investigations than is expected from even the biggest tech giants. In the “worst-case scenario,” Fog Reveal could become a go-to tool allowing police to track abortions in-state and across state lines, EFF policy analyst Matt Guariglia told Ars. Because unlike similar scenarios in which major tech companies like Meta or Google are served warrants compelling them to supply data to police investigating crimes, abortion data surveillance via Fog Reveal could seemingly be conducted without warrants and without any legal oversight. That invisibility could be a desirable feature as states prepare to strictly enforce laws across state lines that either shield or block access to abortion. No one can protest another state using the tool if it’s never named in court, and that, Guariglia told Ars, is often the case with Fog Reveal. As one Maryland-based sergeant wrote in a department email—touting the benefit of “no court paperwork” before purchasing Fog Reveal—the tool’s “success lies in the secrecy.”