Rabbi Etshalom asks about students standing for all guests who walk into the classroom.
Ordinary people who walk into the classroom who do not fall into the halakhic categories of sayva (elderly) or zaken (scholarly) should not be recognized by standing. I would go so far as to say that if a parent walks into the room, his or her child should not rise to honor their parent if they do not do so in other settings.
Students can be taught that rather than standing up in the classroom for everyone, they should take care to stand – especially in non-classroom situations, like a bus or subway – for those people who they are obligated to honor.
Abie