In 2007, Judge Richard Posner found it “untenable” that attaching a tracking device to a car is a seizure. But the Supreme Court struck down warrantless attachment of a GPS device to a car on that basis in 2012. Putting a tracking device on a car makes use of it without the owner’s permission, and it deprives the owner of the right to exclude others from the car.
The weird world of data requires us to recognize seizures when government agents take any of our property rights, including the right to use and the right to exclude others. There’s more to property than the right to possession.
In an amicus brief filed with the U.S. Court of Appeals for the D.C. Circuit last week, we argued for Fourth Amendment protection of property rights in data. Recognition of such rights is essential if the protections of the Fourth Amendment are going to make it into the Information Age.
The case arises because the government seized data about the movements of a criminal suspect from his cell phone provider. The government argues that it can do so under the Stored Communications Act, which requires the government to provide “specific and articulable facts showing that there are reasonable grounds to believe that [data] are relevant and material to an ongoing criminal investigation.” That’s a lower standard than the probable cause standard of the Fourth Amendment.
As we all do, the defendant had a contract with his cell phone provider that required it to share data with others only based on “lawful” or “valid” legal processes. The better reading of that industry-standard contract language is that it gives telecom customers their full right to exclude others from data about them. If you want to take data about us that telecom companies hold for us under contract, you have to get a warrant.