Interesting. I am curious to see how well it works. The UK (which is developing two apps in parallel, one based on the Google/Apple API and one based on a proprietary protocol similar to PEPP-PT) has found in a large scale trial that though the technology worked relatively well, people did not respond well to being told to isolate by an app.

It would be ironic if after weeks of passionate arguments on HN and other places about the technology and about finding the right balance between efficacy and privacy, the whole thing fails because people don't like the principle.