Comment by Happily2020

If one is going through the hassle of joining a video call on a different device to then scan it with their smartphone, all to just connect with another person, you could reasonably assume that they're friends.

Maybe if there's a "celebrity" that displays it on a live stream, that's a bigger issue, but there could be other mechanisms to dissuade this behaviour. Perhaps you could only add one friend with one QR code.