If the threshold was set too low, then the screening process would have too many false positives and potentially overburden it beyond being effective at all. W

If the threshold was set too low, then the screening process would have too many false positives and potentially overburden it beyond being effective at all. While I completely understand where you are coming from, I have to completely disagree on the grounds that we are talking about a single person here. We literally only care about this single person at this point time, and their actions could significantly affect the entire US prognosis in the immediate term. When we are so laser focused, there is no excuse for not being absolutely 100% careful for 21 days.