I was watching some cop show recently where one of the two partners sees somebody, who the other partner (who isn’t in the scene) already knows is a criminal. Part of the dramatic tension came from the fact that the first cop didn’t know they were talking to a bad guy.
In real life this kind of thing can still happen, but maybe not for long. There is a big push in the U.S.A. for cops to wear video cameras (for entirely different reasons), and it is already possible to algorithmically label and match faces in a video.
If you put those things together, then one partner will always be able to know when they are seeing somebody who was already seen by the other partner. And they might even be able to identify that person by name.
Of course the implications of this are much more general. When people are aware, as a matter of course, that we know who they are, what will change? What will stay the same?
There is an argument to be made, drawing from our collective experience with earlier technologies, that this change will lead to more civilized discourse. After all, participants in on-line forums where everyone must use their real name tend to be much more polite than people in forums where everyone is anonymous.