Eh, I think it’s potentially useful even if everybody recognizes it. It’s superficially similar enough to a normal wave hello and fast enough to perform that it

Eh, I think it’s potentially useful even if everybody recognizes it. It’s superficially similar enough to a normal wave hello and fast enough to perform that it could be done surreptitiously (as opposed to frantically waving for help or elaborate pantomime). I’m not sure if it’s useful or just a feel-good thing, but I don’t think us non-domain-experts can reject the former without more info.