If Apple was performing scans on their cloud servers, you'd be absolutely right. But if the scanning is being done on the individual's device, I'm not sure it's that straightforward. The third party doctrine surely cannot apply if the scanning is performed prior to the material being in third party hands.
Therefore if the Government forces Apple to change the search parameters contained within private devices, I cannot see how this would work around the 4th Amendment.
If this is correct, it might be possible to argue that Apple's approach has (for Americans) constitutional safeguards which do not exist for on-cloud scanning performed by Google or Microsoft.
I read the article; I don't think they highlighted this specific point that on-device scanning has a potential, hypothetical constitutional advantage in comparison to Google, Microsoft and Facebook who scan exclusively in the cloud.
> The 4A protections don't apply to third parties.
The government can't pay someone to break into your house and steal evidence they want without a warrant. I mean, they can, but the evidence wouldn't be admissible in court.
They don't need a warrant. You gave data to someone else. That someone isn't bound to keep it secret. They can demand a warrant if they are motivated by ethical principles but that is optional and potentially overruled by other laws.
But if they're looking for incriminating evidence on your private property (i.e. on-device scanning) then they do need a warrant. It doesn't matter if a copy of it was also given to a third party (i.e. uploaded to iCloud) what matters is where the actual search takes place.
The authorities aren't doing the scanning. You will be made to agree in the fine print to let Apple do it when iCloud sync is enabled. If they run across evidence of a crime then c'est la vie.
The sort of questions about 4A protections here haven't really been tested. Third party doctrine might not apply in this circumstance and the court is slowly evolving with the times.
In Carpenter v. United States (2018), the Supreme Court ruled warrants are needed for gathering cell phone tracking information, remarking that cell phones are almost a “feature of human anatomy”, “when the Government tracks the location of a cell phone it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone’s user”.
...[cell-site location information] provides officers with “an all-encompassing record of the holder’s whereabouts” and “provides an intimate window into a person’s life, revealing not only [an individual’s] particular movements, but through them [their] familial, political, professional, religious, and sexual associations.”
