> On the whole, I'm not quite sure how the Apple plan will protect actual children from rape (except to somewhat reduce the secondary harm of distribution).

You bring up the distinction between "possession offenses" (i.e., a person who has CSAM content) and "hands-on offenses" (i.e., a person who abuses children and possibly, but not necessarily, produces CSAM). Detecting possession offenses (as Apple's sytem does) has the second-order effect of finding hands-on offenders because hands-on offenders tend to also collect CSAM and form large libraries of it. So finding a CSAM collection is the best way to find a hands-on offender and stop their abuse. Ideally, victims would always disclose their abuse so that the traditional investigatory process could handle it -- but child sexual abuse is special in that offenders are skilled in manipulating children and families in order to avoid detection.

I think that the case of USA v. Rosenchein [0] is a good example because it shows the ins and outs of how the company->NCMEC->law enforcement system tends to work and how it leads to hands-on offenders. It's higher profile than most, perhaps because the defendant (a surgeon), seems to have plenty of resources for fighting the conviction on constitutional grounds (as opposed to actually claiming innocence). But the mechanism leading to the prosecution is by no means exceptional.

Caveat: Not a lawyer.

[0] https://www.anylaw.com/case/usa-v-rosenchein/d-new-mexico/11...