Right. Requiring exact matches for this kind of material is absurd as a single pixel change would foil any detection. So everyone, practically speaking, trying to detect it is going to use some form of hash algorithms. And every hash algorithm, by definition, permits potential collisions and false positives. Which is why any sensible program will use a manual review process before pushing anything forward to law enforcement. Apple's system, requiring ~30 matches, means that you'd have to have 30 or so false positives that also happen to look like CSAM to manual reviewers to end up getting a false case sent off to law enforcement.