The core flaw, AFAICT, of every contact tracing app proposal I’ve seen is that there are entire industries (service, factory, and more) where workers are required to leave their phones in their lockers (or equiv.) before they start their shift and only get to use them on breaks.

@baldur Including Apple Store employees! I would have to dig back a little to find that reference, but I think it was a well-known one like Daring Fireball.