Virtual Reality and Augmented Reality in your home can involve the creation of an intimate portrait of your private life.  The VR/AR headsets can request audio and video of the inside of our house, telemetry about our movements, depth data and images that can build a highly accurate geometrical representation of your place, that can map exactly where that mug sits on your coffee table, all generated by a simultaneous localization and mapping (SLAM) system.  As Facebook’s Reality Labs explains, their “high-accuracy depth capture system, which uses dots projected into the scene in infrared, serves to capture the exact shape of big objects like tables and chairs and also smaller ones, like the remote control on the couch.” VR/AR providers can create “Replica re-creations of the real spaces that even a careful observer might think are real,” which is both the promise of and the privacy problem with this technology.

If the government wants to get that information, it needs to bring a warrant. 

Nearly twenty years ago, the Supreme Court examined another technology that would allow law enforcement to look through your walls into the sanctity of your private space—thermal imaging. In Kyllo v. United States, the Court held that a thermal scan, even from a public place outside the house, to monitor the heat emanating in your home was a Fourth Amendment search, and required a warrant.  This was an important case, building upon some earlier cases, like United States v. Karo, which found a search when the remote activation of a beeper showed a can of ether was inside a home. 

More critically, Kyllo established the principle that new technologies1 that can “explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a 'search' and is presumptively unreasonable without a warrant.” A VR/AR setup at home can provide a wealth of information—“details  of the home”—that was previously unknowable without the police coming in through the door.

This is important, not just to stop people from seeing the dirty dishes in your sink, or the politically provocative books on your bookshelf.  The protection of your home from government intrusion is essential to preserve your right to be left alone, and to have autonomy in your thoughts and expression without the fear of Big Brother breathing down your neck. While you can choose to share your home with friends, family or the public, the ability to make that choice is a fundamental freedom essential to human rights.

Of course, a service provider may require sharing this information before providing certain services.  You might want to invite your family to a Covid-safe housewarming, their avatars appearing in a exact replica of your new home, sharing the joy of seeing your new space. To get the full experience and fulfill the promise of the new technology, the details of your house—your furnishings, the art on your walls, the books on your shelf may need to be shared with a service provider to be enjoyed by your friends. And, at the same time, creating a tempting target for law enforcement wanting to look inside your house. 

Of course, the ideal would be that strong encryption and security measures would protect that information, such that only the intended visitors to your virtual house could get to wander the space, and the government would be unable to obtain the unencrypted information from a third-party.  But we also need to recognize that governments will continue to press for unencrypted access to private spaces. Even where encryption is strong between end points, governments may, like the United Kingdom, ask for the ability to insert an invisible ghost to attend the committee of correspondence meeting you hold in your virtual dining room. 

While it is clear that monitoring the real-time audio in your virtual home requires a wiretap order, the government may argue that they can still observe a virtual home in real-time. Not so.  Carpenter v. United States provides the constitutional basis to keep the government at bay when the technology is not enough.  Two years ago, in a landmark decision, the Supreme Court established that accessing historical records containing the physical locations of cellphones required a search warrant, even though they were held by a third-party. Carpenter cast needed doubt on the third-party doctrine, which allows access to third-party held records without a warrant, noting that “few could have imagined a society in which a phone goes wherever its owner goes, conveying to the wireless carrier not just dialed digits, but a detailed and comprehensive record of the person’s movements.”

Likewise, when the third-party doctrine was created in 1979, few could have imagined a society in which VR/AR systems can map, in glorious three dimensional detail, the interior of one’s home and their personal behavior and movements, conveying to the VR/AR service provider a detailed and comprehensive record of the goings on of a person’s house. Carpenter and Kyllo stand strongly for requiring a warrant for any information created by your VR/AR devices that shows the interior of your private spaces, regardless of whether that information is held by a service provider.

In California, where many VR/AR service providers are based, CalECPA generally requires a warrant or wiretap order before the government may obtain this sensitive data from service providers, with a narrow exception for subpoenas, where “access to the information via the subpoena is not otherwise prohibited by state or federal law.”  Under Kyllo and Carpenter, warrantless access to your home through VR/AR technology is prohibited by the ultimate federal law, the Constitution.

We need to be able to take advantage of the awesomeness of this new technology, where you can have a fully formed virtual space—and invite your friends to join you from afar—without creating a dystopian future where the government can teleport into a photo-realistic version of your house, able to search all the nooks and crannies measured and recorded by the tech, without a warrant. 

Carpenter led to a sea change in the law, and since has been cited in hundreds of criminal and civil cases across the country, challenging the third-party doctrine for surveillance sources, like real-time location tracking, 24/7 video cameras and automatic license plate readers. Still the development of the doctrine will take time. No court has yet ruled on a warrant for a virtual search of your house.  For now, it is up to the service providers to give a pledge, backed by a quarrel of steely-eyed privacy lawyers, that if the government comes to knock on your VR door, they will say “Come back with a warrant.” 

• 1. Kyllo used the phrase “device that is not in general public use,” which sets up an unfortunate and unnecessary test that could erode our privacy as new technologies become more widespread. Right now, the technology to surreptitiously view the interior of a SLAM-mapped home is not in general use, and even when VR and AR are ubiquitous, courts have recognized that technologies to surveil cell phones are not “in general public use,” even though the cell phones themselves are.