I suspect they’ll quickly revert to email for the paper trail, even for authenticationPolice departments call Apple and say "hey this is me, my email address is xxx", Apple builds an app with a registration system and the police are given an access code via email, the app then registers them for 2 factor. Someone at Apple tries to confirm the details of the police department, ie did they call from a VOIP number or a traditional phone line, does the email make sense, etc. If they can't confirm it they can send people over and talk in person.