… but this technology is pretty much available *now* and I can see this app hitting the market soon. If something like Google Glass ever makes a return, I can see an app like this running in real time, providing an augmented reality overlay letting the user know the enemy-status of nearly everyone they see on the street. Such an app would be used by extremists on both sides in order to find people to ambush and assault; it would be used by the vast majority in the middle to find those that they should avoid.
The existence and widespread adoption of such a thing would speed the process of people disguising themselves in public. A year ago I thought sure that the pandemic would do it, but instead we’ve got goons beating the tar out of people for wearing/not wearing simple and dubiously useful masks.