Drones now come in all shapes and sizes, and they can be used in a variety of settings for surveillance.

Advanced camera technology can capture photos and video from 1,000 feet away, while machine learning software can remotely identify who we are and lock on to and follow our bodies as we move around—all without our knowledge.

They can also intercept mobile phone calls, gather license plate information and determine whether someone is carrying a weapon. In the U.S., drones are regularly used by federal, state and local public safety agencies including the FBI, ICE, U.S. Marshals and Coast Guard.

Wide-area motion imagery technology allows police to surreptitiously track any person or vehicle without being seen. Drones will soon enable the mass tracking of people at concerts, vehicles on the highway, amusement park attendees—the sorts of crowded public settings we may already expect to be under some form of surveillance by law enforcement. (See also: Drones Section.)