Two articles discussing the same issue.
First, undercover police officers used smartphones while mingling with protesters in Tampa, Florida, during the Republican National Convention. While this may not be newsworthy in and of itself, how they used the phones is newsworthy. The phones had facial recognition software on them and were linked to surveillance cameras and databases of known offenders. Used in this manner, it was a test-run for future programs nation-wide.
Similarly, in Los Angeles, California, the police department is currently tracking cell phones by “electronically impersonat[ing] a cellphone tower and dupes the mobile phone into connecting through its own antennae.” The article discusses the case of David Rigmaiden out of Arizona where the FBI used the same technology without a warrant. This is one case I will continue to monitor.