> How will Apple know whether a hash is for non-CSAM content? Spoiler alert: they won’t.
As I said, the flagged content is reviewed by an Apple employee before it actually triggers an external report. If the flagged material is not in fact CSAM, it will not be reported.
> And Apple claims it will be reviewed by a human. Sure, just like YouTube copyright claims? Or will it get automated in the near future? And what about in China? Or Saudi Arabia or other countries with less human rights?
First of all, the volume of flagged CSAM content is much, much smaller than the volume of YouTube copyright claims. It's entirely plausible to ensure that a human reviews all flags. Second, Apple is actually constitutionally-barred from automating this step entirely. You can thank Neil Gorsuch's decision in United States v. Ackerman for this. [1] The crux is that since NCMEC is a qausi-governmental entity, automatically sending CSAM-matched content to NCMEC without an Apple employee first inspecting the content would constitute an unreasonable search and seizure and would violate the 4th amendment.
[1] https://library.law.virginia.edu/gorsuchproject/united-state...