I'm sure it's region specific tbh. I've noticed it a lot here in the US, but I'm sure it's different in other places. You do have a point that maybe it's just become more obvious that they don't want to be bothered. I also think it has to do with a change within myself lately. When I was more standoffish, and to myself I never paid it any attention. Now it's becoming way more obvious since I've become a little bit more outgoing I guess. Everyone has unique experiences with this sort of thing so I was just giving my own opinion about it.