You’ve got it mixed up. The messages are scanned for any explicit material (which in many but not all cases is illegal), not specific hash matches. That’s only for uploads to iCloud Photos.
Additionally, you are not “obliged” to report such photos to the police. Uninvolved service providers do have to submit some sort of report iirc, but to require regular users to do so would raise Fifth Amendment concerns.
No, I’m not. You’re confusing the issues. If you have a child’s account, joined to your family group, you will get alerted about explicit images — if you decide to use it.
The photos that you are obliged to report are child pornography that match a hash in a database used everywhere. If you don’t report, you’re in a place where you may have criminal liability.
