You presume Apple and the DoJ will implement this with human beings at each step. They won't. Both parties will automate as much of this clandestine search as

You presume Apple and the DoJ will implement this with human beings at each step. They won't. Both parties will automate as much of this clandestine search as possible. With time, the external visibility and oversight of this practice will fade, and with it, any motivation to confirm fair and accurate matches. Welcome to the sloppiness inherent in clandestine law enforcement intel gathering. As with all politically-motivated initiatives that boldly violate the Constitution (consider the FISA Court, and its rubber stamp approval of 100% of the secret warrants put before it), the use and abuse of this system will go largely underground, like FISA, and its utility will slowly degrade due to lack of oversight. In time, even bad matches will log the IDs of both parties in databases that label them as potential sexual predators. Believe it. That's how modern computer-based gov't intel works. Like most law enforcement policy recommendation systems, Apple's initial match algorithm will never be assessed for accuracy, nor be accountable for being wrong at least 10% of the time. In time it will be replaced by other third party screening software that will be even more poorly written and overseen. That's just what law enforcement does. I've personally seen people suffer this kind of gov't abuse and neglect as a result of clueless automated law enforcement initiatives after 9-1-1. I don't welcome more, nor the gradual and willful tossing of everyone's basic Constitutional rights that Apple's practice portends. The damages to personal liberty that are inherent in conducting secret searches without cause or oversight is exactly why the Fourth Amendment requires a warrant before conducting a search. NOW is the time to disabuse your sense of 'daftness'; not years from now, after the Fourth and Fifth Amendments become irreversibly passe. Or should I say, 'daft'?