[peq]

As I understand this, the approach here is to bet on personal responsibility. This technology cannot be used to enforce quarantines as the authorities have no access to the data.

Basically, we have to stop 2/3 of infections to get an R<1. If 2/3 of the population use the app honestly and we keep up some other measures (no indoor events where people are in close contact, wearing masks while shopping, no visitors in nursing homes and hospitals, etc.) then this might be enough to contain the virus until we have a vaccine.