Yes, healed patients who don't produce viruses any more aren't important, but anyone still infectious is still a danger. Even if you are supposed, often even legally required, to stay at home while being infected, there is no guarantee you aren't. I'd bet that most of these people also take their phones with them, after all far more serious criminals like actual murderers are often taking their phones to sites of crimes as well. The IDs of those devices are still relevant. Quarantine after diagnosis may last up to 14 days, so your phone should be uploading IDs for 14 days to the diagnosis server.
Given continuation of exponential spread, we aren't far from having 3 million new patients within a span of two weeks in populous countries like the US.
It’s new patients only, but for each day they might have been infectious. So, if it’s 100k new cases a day, and each uploads 5 days of keys, then it’s 8 MB.
Seems doable, especially considering that you’d want to have fully blown lockdown during the exponential growth, and only then switch over to this contact tracing phase once the initial wave has abated.
Yes, healed patients who don't produce viruses any more aren't important, but anyone still infectious is still a danger. Even if you are supposed, often even legally required, to stay at home while being infected, there is no guarantee you aren't. I'd bet that most of these people also take their phones with them, after all far more serious criminals like actual murderers are often taking their phones to sites of crimes as well. The IDs of those devices are still relevant. Quarantine after diagnosis may last up to 14 days, so your phone should be uploading IDs for 14 days to the diagnosis server.
Given continuation of exponential spread, we aren't far from having 3 million new patients within a span of two weeks in populous countries like the US.