In addition to high-resolution photographic and video cameras, police drones may be equipped with myriad spying payloads, such as live-video transmitters, thermal imaging, heat sensors, mapping technology, automated license plate readers, cell site simulators, cell phone signal interceptors and other technologies. Captured data can later be scrutinized with backend software tools like license plate readers and face recognition technology. There have even been proposals for law enforcement to attach lethal and less-lethal weapons to drones and robots.

Over the past decade or so, police drone use has dramatically expanded. The Electronic Frontier Foundation's Atlas of Surveillance lists more than 1500 law enforcement agencies across the US that have been reported to employ drones. The result is that backyards, which are part of the constitutionally protected curtilage of a home, are frequently being captured, either intentionally or incidentally. In grappling with the legal implications of this phenomenon, we are confronted by a pair of U.S. Supreme Court cases from the 1980s: California v. Ciraolo and Florida v. Riley. There, the Supreme Court ruled that warrantless aerial surveillance conducted by law enforcement in low-flying manned aircrafts did not violate the Fourth Amendment because there was no reasonable expectation of privacy from what was visible from the sky. Although there are fundamental differences between surveillance by manned aircrafts and drones, some courts have extended the analysis to situations involving drones, shutting the door to federal Constitution challenges.

Yet, Americans, legislators, and even judges, have long voiced serious worries with the threat of rampant and unchecked aerial surveillance. A couple of years ago, the Fourth Circuit found in Leaders of a Beautiful Struggle v. Baltimore Police Department that a mass aerial surveillance program (using manned aircrafts) covering most of the city violated the Fourth Amendment.