All of us can only guess how much "fuzz" is being allowed for in their hash matches. I see no reason to believe Apple phoned in their analysis which leads them

All of us can only guess how much "fuzz" is being allowed for in their hash matches. I see no reason to believe Apple phoned in their analysis which leads them to be confident in a false positive rate of 1 in 1 billion per iCloud account. While we can only guess, they actually know how their algorithm behaves, and I dare say they've validated it against tens of millions, if not hundreds of millions of real customer images.