Good points. In therapy training you learn to look for the difference between the content and the process. Most of the time in these situations there is a reason that the student won't move and the student believes they are acting rationally and are somehow in the right. That is the process that gets missed because we are only paying attention to the content(i.e. her refusal to move).
To be effective (I'm assuming teachers and staff want to be effective with students) you have to address the process as best you can. For example in this type of situation, step back and say "ok, hold on, we have a class to teach and we can't do that if you continue to stay in your chair and for your privacy and ours we need to address this situation in private (content). We don't understand why you refuse to move but are willing to listen once we get to the office. Is there anyone in the building that could help move this along? Or is there someone I can get on the phone so we can move out and let the class resume? (process)"
That question tells the student that we recognize there is something else going on underneath the refusal and gives them a way out of the situation.
Unfortunately we are in a period of reacting strongly to the content without even thinking there may be some process happening internally. Teachers, administrators and school resource officers get offended way too easily when their authority is challenged without even thinking there may be a good reason for that authority to be challenged. Don't think, just obey, otherwise...