[csnover]

You’re assuming that most people will act responsibly and not go about their daily lives infecting other people if they know that they don’t know. This goes against my personal experience of how many humans behave.

It’s equally plausible to me that someone receiving a false negative will take extra precautions in order to avoid becoming sick themselves, instead of deciding (in the absence of a test) that they are infected and so don’t need to be careful about protecting themselves any more.