Fair enough.
These days, if I walk around town for 30 minutes or drop into CVS or Home Depot for 15 minutes, what are the chances that I will NOT pass by somebody who has it? With the ultra sensitivity of RT-PCR, what are the chances that infected person is actually contagious?
If the alarm goes off all the time, then we all hunker down at home all the time. How is that different from what we are doing now?
Depends entirely on the area really, and how crowded the stores are and how long you're spending in there.
"With the ultra sensitivity of RT-PCR, what are the chances that infected person is actually contagious?"
That's currently unknown. What's been shown so far is that most people who are infected don't pass it to anyone. Some pass it to a small number of people. And a small number of people pass it to huge numbers of others. What isn't clear is how much of that is a difference in infectiousness between those persons and how much of that is due to changes in behaviors.
If the alarm goes off all the time, then we all hunker down at home all the time. How is that different from what we are doing now?
I agree that if it's just going off all the time, it has no value. I don't know how exactly this system is set up or operates and I have no data to say this particular implementation works well or is garbage. I was only responding to the question about what utility there would be in knowing you had been exposed to infected persons.