Bowwow:
I have never sat in the Rav’s seat, but to be fair, I never wanted to. So I don’t know what I would do if I wanted to.
If there is a talis bag on the seat, I would not move it and sit down.
If there are name plates on the seat, I would sit there anyway.
I think I am acting fine and normally. I think I am permitted to sit down even though I am a guest, and every seat is as likely to be someone’s seat as the next.
If you don’t like it, daven at home.