That's it, you nailed it. What's more likely, a population that gets all infected all at the same time, or one person infected being careless with samples? Th

That's it, you nailed it. What's more likely, a population that gets all infected all at the same time, or one person infected being careless with samples? Then there's more: given how many tests of similar populations are getting done, what are the chances that some have a careless infected tester?