it's kind of silly how this is treated like some deeply technical issue. Apple's 'one of a trillion' claim is either true and the software is useless, because I'm pretty sure pedophiles can figure out what a watermark or a gaussian blur in paint net is, or it's imprecise and actually detects things which is the very thing that makes it dangerous to the public.
It's a direct trade-off and the error tolerance of any such filter is the only thing that makes it useful so we can basically stop arguing about the depths of implementation details or how high the collision rate of the hashing algorithm is etc. If this thing is supposed to catch anyone it needs to be magnitudes more lenient than any of those minor faults.