Recently, the 4th Circuit Court of Appeals had a variety of concurring opinions regarding the case of US v. Chatrie . βοΈ ( https://www.ca4.uscourts.gov/opinions/224489.P.pdf )
The basic facts: in 2019, a bank in Virginia was robbed. The police used a geofence warrant to request information from Google related to the individuals with cell-phones in the vicinity of the crime. One of those individuals was Chatrie, who was later identified as the suspect. Chatrie eventually pled guilty, conditional to the geofence evidence being admissible.
My views align with none of the opinions in full.
1. Was this a "search"?
Yes. Google, through an informal process involving their own counsel and external law-enforcement, developed a three-step process for geofence warrants. That process is not freely available to all law-enforcement for any reason, but requires a warrant to be issued.
The detailed information is private; it includes the person's name, additional personal information, as well as their location. Furthermore, Google has a business interest in keeping this information private, and makes representations that it will do so to the extent of the law.
There is no way this was not a "search" in some form, governed by the protections of the 4th amendment.
I do have some amount of a contrary view to the 4th Amendment interpretation. There is no direct burden on the person being searched here. (At least as long as one assumes the search is against Chatrie, rather than Google). No government agents are entering houses, examining physical papers, etc. The extension of the 4th amendment to an abstract right of privacy-of-information, rather than security against physical intrusions, is not something I am willing to agree with in an unqualified manner.
2. Can a "geofence" warrant be allowed under probable cause? I give an unqualified "yes".
As a result, whether this specific geofence warrant complied with a not-yet-expounded procedure is irrelevant; the "good-faith" exception to exclusion of the information would apply, and the information would not be excluded regardless of whether this exact procedure is endorsed.
Several opinions specify that the first step of the process is (or at least should be) designed to not include any "private" information. Later steps, by contrast, contain sufficiently-detailed information as to be "uncloakable", or on-its-face identifying information. π‘ ( the arguments that the later steps should require a separate warrant are somewhat compelling; I take no position on them.)
In addition, Carpenter v. United States is frequently referenced, in the context of "cell-tower records". While the exact details of opt-in v. opt-out are heavily discussed, I personally don't find that a meaningful distinction.
The warrant clearly described the "place to be searched": Google records, as provided to the government by Google.
While some of the specific concerns (should each step of the process require a magistrate's approval) may be resolved differently, I see no way that the general concept of such a warrant is impermissible.
A warrant for a nearby business's security camera footage might have similar privacy issues, but it is clearly allowable. The fact that some of the individuals might have been "entering a private space" is not a reason to disallow it.
The arguments are focused on whether it was a search; once it is stipulated that it is a search, the overarching arguments against this type of search collapse. A "reasonable expectation of privacy" cannot prevent one from being subject to a warrant, and whether one is identified by name or as the person possessing a specific cell-phone is irrelevant.
A warrant does not require naming the exact individuals being searched, especially in a situation where they are not physically burdened by the search.
One additional footnote of note: The Fifth Circuit has held βthat geofence warrants are general warrants categorically prohibited by the Fourth Amendment.β
This is an aggressive take, far beyond the text of the Fourth Amendment.
One can imagine an argument that such a warrant will, necessarily, be a privacy violation. In fact, there is one argument in the case, presented as a hypothetical by Judger Berner: Obtaining a warrant would require probable cause to search all individuals who fall within a particular geofence. The government would thus need to show probable cause that every individual near the scene of a crime was involved in the crime or witnessed it.
That standard is wrong. A de minimis privacy violation, which occurs without the awareness of the person involved and does not lead to any harms against them, should not throw out the entire tree of evidence.
More broadly, the claim that technology that might violate a privacy right is inherently illegal when used for law-enforcement is absurd on its face. It is also not supported by the Constitution, federal law, or the population at-large.