Oh really how does it work?
See this is where this is going….

No one knows what language will dictate assignments.
If FO vacancies go unfilled, they can hire into it. Its possible.
If Captain vacancies go unfilled….what? One of you seem to know exactly ….
Then the company can junior assign into that seat, although we have no language for that specifically.
This will be up to the arbitrator and writing the language for these scenarios, none of know.