But police drones are no joyous party gift. As they make their way into more police departments across the country, we should be prepared to face the difficult civil liberties concerns they present.

Police departments have made clear that they value aerial surveillance. Reporting in August revealed that police in Baltimore had for months secretly taken advantage of aerial cameras designed by Persistent Surveillance Systems (PSS), a company that — unsurprisingly — makes surveillance equipment. This equipment was attached to Cessna aircraft and allowed PSS analysts to access to what its developer called “Google Earth with TiVo.” The cameras mounted on a single airplane can cover an area of around 30 square miles. After a crime is committed analysts can focus on the scene and fast‐​forward or rewind footage to see where the suspect came from or is hiding. PSS has not just been deployed in Baltimore; it has also been used in Philadelphia, Compton, and Dayton, Ohio.

Dayton police chief Richard Biehl expressed admiration for the technology in 2014, saying, “I want [the public] to be worried that we’re watching […] I want them to be worried that they never know when we’re overhead.” This passion for constant surveillance is not unique to Biehl. Indeed, law enforcement agencies across the country have used a wide range of tools such as cell‐​site simulators, social media trackers, and others to spy on citizens.

It’s easy to imagine how drones could be used for surveillance. Drones provide an aerial platform for surveillance tools and are much cheaper than airplanes or helicopters. They are also easier to operate than manned aerial vehicles, requiring much less training.

In the private sector, drone technology is improving at a dramatic rate. Facebook recently announced that its internet‐​delivery drone, which has a wingspan larger than a Boeing 737’s, had successfully completed its first test flight. The hope is that the drone will be able to stay aloft for months at a time. We should expect such developments to spill over into law enforcement.

Military drone surveillance technology currently exists that allows users to see six‐​inch details in an area the size of a small city. While presently too expensive for many law enforcement agencies, we shouldn’t be in any doubt that when this technology is affordable police would seize on the opportunity to put it to use. Such equipment on a drone that can stay airborne for months ought to worry citizens who are used to going about their business without having their every move caught on flying cameras.

It’s possible that some of the survey respondents not worried about police drones infringing on their privacy take a “I’ve done nothing wrong, so I have nothing to hide” approach. They should reconsider their position. As drone technology improves law enforcement will be able to gather a wide range of data on citizens engaging in perfectly legal activity that they may not want police to know about, such as participating in an extramarital affair, visiting a gun show, protesting, or attending a mosque or an Alcoholics Anonymous meeting. It’s true that persistent surveillance technology attached to an airplane or drone could help investigators track where a suspected burglar or murderer lives, but absent oversight there’s no reason why the same technology couldn’t be used to track protesters, gun owners, Muslims, and others.

Drones are one of the latest technologies that require us to consider how much privacy we are willing to cede in the name of security and safety. They might seem relatively rare and harmless at the moment, but police drones will be more prolific and intrusive in the not too distant future. Americans pondering questions about police drones and their privacy must consider these factors, even if they think they have nothing to hide.