A pinch of salt would ruin them for sure. The good thing about testing a bunch of people in contact at the same time is that even with false positives and negatives and badly done tests, getting a few positives in a group makes it more likely it's right.
A pinch of salt would ruin them for sure. The good thing about testing a bunch of people in contact at the same time is that even with false positives and negatives and badly done tests, getting a few positives in a group makes it more likely it's right.