They unanimously found that the government needs a warrant to put a GPS tracker on your car.
Similar to this case, the state argued that a cop didn't need a warrant to follow a car, so why was a GPS tracker any different? It just made the police work more efficient. The court disagreed.
I don't see how that would apply here.
Strictly speaking, only Sotomayor concurred in the original decision, Alito, Ginsburg, Breyer, and Kagan concurred in the judgement (that is, the result).
The difference is significant in general, because the decision includes the rationale, and the Alito opinion (joined by Ginsburg, Breyer, and Kagan) disagrees with the rationale of the majority opinion. (That is, the majority held trespass to be decisive, Sotomayor agreed that it was in this case, but explicitly wrote a concurrence to argue that trespass wasn't necessary for a violation, and the other four agreed that GPS was a violation, but disagreed that trespass was an appropriate consideration.)
That is, there were four justices who believed that the GPS tracker was a violation because of the trespass to the target's property, four justices who though it was a violation for other reasons, but not because it was trespass to property, and one who thought it was violation because of trespass to property as well as other reasons.
Which results in the interesting situation, in that there were different (but overlapping with Sotomayor in both) 5-vote majorities both for the violation due to trespass view and the violation due to reasons-other-than-trespass view.
One of these things is not like the others. Did Alito take the same position as the others listed here?
They may not however tamper with your personal property.
If you do not own the car and say it's a company car the police might also not need a warrant to put a GPS tracker on it if they get consent from your employer, this might also cover rental cars (not sure about leases).
That to me would be a pretty clear line between a passerby and law enforcement in this case.
"I'm curious: would they need a warrant to sit in a car outside someone's house to watch them? " -Zak
The police doesn't need a warrant for most things they due in their line of duty, most warrants are requested to compel instead of risking seeking consent not because the law mandates judicial approval.
This is true but not for the reason you cite. It would be stalking if they make a statement that will place the person in reasonable fear of harm. If they did that, in most states, it won't matter whether they are doing it as cops or not. Some states have "no lawful justification" in the text (which would protect police), but most don't.
Various states do have laws that would cover this that are not stalking (violations of various invasion of privacy, wiretapping, etc).
Most are written in the way that it will be unlawful even if they are police.
The Constitution however says nothing about "in their movements" or "in the light they reflect."
You're talking about placing a EULA on receiving visible light. That the photons have interacted with your person doesn't make them yours. Trying to tell people what they can and can't do with incoming visible light in a public place is an egregious breach of their freedom.
You simply do not have the authority (morally or practically) to control what happens to other people's observations about you in public spaces. It's not your data, it's theirs. Reaching into people's sensory systems and making rules about what can't get written down or shared is a disgustingly Orwellian violation of their autonomy of thought and freedom of speech.
You have a right to privacy in your enclosed property, over your secure communication channels, etc. When you can be seen from a public place, you simply don't.
On the belief that pervasive surveillance is a societal problem, it might be reasonable to restrict the state from using its property/infrastructure for surveillance camera positions, or to prevent the police from using such a system to go trawling for targets to investigate.
But you absolutely cannot bar a private individual from having cameras on his person/property/car or place restrictions on how he shares that data.
The increasing omniscience of your neighbors brings society back from a relatively short period of anonymity. In a small town, a single officer off the main road knew everyone's comings and goings. This did lead to a lot of abuse, and I'm glad that we're beyond the worst of sheriff as bully. But the answer to increasing observational powers isn't going to be in forcing law enforcement to be crippled, it's going to be in better open access and transparency on what and who they are targeting.
It's one thing to say that "everyone" is under observation when a 360-degree camera is posted on a pole in the middle of town, but another when a single lens camera is posted on the same pole but only pointed at your bedroom window. Now, whether they are legally different is not something that I'm qualified to address, but personally I see a wide difference between the two.
Of course not an easy thing, but it's a lot better than hand wringing about what the courts will gin up.
The argument is always that they're only tracking the "same views enjoyed by passersby on public roads", attempting to create a false equivalence between a camera and a human.
This has always been a pet peeve of mine, because there are factors that nullify the projected equivalence: each of these 'passersby' on the public road can only be in one place at one time. They are not omniscient. Further, there is an assumed limit to the amount of data they can collect (what can one person see from that street corner) and an assumed cost to the collection of that data (and therefore: even a government is limited in the scope of collection; they can't place an agent infront of every house on every street). These were the assumptions present in the time of the writing of the amendment. These assumptions only apply to the economics of humans, not cameras, and materially changes the effect of the law in the present day.
Courts will need a mechanism to articulate that a camera is not equivalent to a passerby. It's not a question of function, it's a question of scope. Much like anti-trust laws or regulations against cornering economic markets don't differentiate based on function, but the scope of the function. When it comes to privacy - the kind that the Fourth Amendment was written to protect - yes, placing agents on corners is substantially different than placing cameras on corners.