I'm so pleased this is a unanimous decision. I hope the phone metadata issue comes before the supreme court. If they are unanimous on this, then I would guess they would rule that metadata on cell phone use is in effect a GPS tracking method. It should fall under the same category.
This and the earlier GPS case, Jones, aren't based on some broad idea that the government can't track you without a warrant. They're based on the fact that placing the GPS on your vehicle violates your property right. You don't have any property right in phone metadata--it's the phone companies data collected for its own purposes. This doesn't apply to Stingray either. In the GPS cases, the government is putting a device on your car that broadcasts your position. With a stingray, your cell phone is reaching out into the world and giving you away.
The comment above (by rayiner) is completely correct. Cell phone tracking has more to do with third party doctrine and the Stored Communications Act than with this case.[1][2]
Question about the third party doctrine. If I hand google drive an encrypted file, do I have a reasonable expectation of the privacy wrt the decrypted data?
Well, the encrypted file would probably not have a "reasonable expectation of privacy". The government would probably acquire the encrypted version from Google, then decrypt it; I don't see why any court would make a finding with respect to the expectation of privacy of the decrypted file.
> You don't have any property right in phone metadata--it's the phone companies data collected for its own purposes.
I'd disagree with that. It's my phone, and the metadata collected by the phone company is done with my consent and under certain terms. If the terms change, I get to change my consent if I want.
It'd be like the FBI sneaking a bug into the lamp I bought at Lowes.
Obviously we're both not lawyers, so there's probably a whole bunch of stuff we're both missing (turns out law is hard).
There is a difference between "your information" and "information about you." Not just a legal one, but a epistemological one. AT&T doesn't need your permission to keep track of requests on their network any more than Lowes needs your permission to keep track of who buys a lamp.
That said, this is an issue where nitpicky legal and technical analysis is probably going to take a back-seat to politics. After Riley v. California, it seems quite possible that the Supreme Court is ready to say: "it doesn't matter that Mark Zuckerberg can see all your photos if he wants--the 4th amendment applies to the cloud because we want it to."
Remember folks, this doesn't prevent the government from tracking you; It just means that if they try to use the evidence gained from tracking you in a court of law, you can pay a lawyer to get that evidence suppressed.
The CIA can still use tracking devices and so can the police in a state without good public defenders just as the NSA is free to go beyond the bounds of a FISA court warrant. Nobody checks them and the warrants' validity is never brought before an appellate court.
At least in theory, actual physical installation of a tracking device without authorization would violate trespassing laws in many cases. So even if the government doesn't try to introduce the results as evidence, it might be possible to file a civil trespassing suit. But, I have no idea what the odds of actually prevailing on that are (probably low).
My reading of this is that the problem is less with the data and more with the placing of a tracker on a person or their property because the fourth amendment says you have a right to be secure in those things.
I think the key word is unreasonable. I can reasonably expect that a GPS tracker has not been placed on my car. On the other hand, I knowingly and voluntarily carry a cell phone, so the question is then whether I could reasonably expect to be able to be tracked. I think some people might not understand that this is possible, but a growing number do understand this.
