A Third Solution
Not only is it completely unrealistic at scale, the specific approach in the blog post is wildly impossible  at all.It requires screeners to directly manipulate saliva samples; this is dangerous in a pandemic.  The assays referred to (lazily) in a Google Scholar search are almost overwhelmingly antibody assays; this does not allow the screener to differentiate between "has COVID-19" and "had COVID-19".  Also, there is no evidence that the described test actually exists.Finally, maybe irrelevantly, there is no way in hell you're going to get people at large to stand around for two hours a week waiting for test results.  Ten minutes for a screening whenever you try to enter a public building; that's ten minutes to get into work, and we'll say ten minutes to get into another place each day.  "But wait," I hear you say, "you only need to be screened once per day, and the first place can share that data with the next place."  This plan was constructed by someone who is unfamiliar with medical records laws.This is no "third solution."   It's an engaging thought experiment, but it's just too far away from reality to get here from there.