Who cares whose aircraft it is, it is never really yours otherwise you would be a fool not to retire.
If some jobsworth wants to sit in the pilots seat and dictate the rules so be it. As others have said, be polite and if that gets you nowhere report it as the delay in the CAR. After the continued show of contempt by our managers why do any of you even get to the point of caring about a delay. Do your job professionally and politely but honestly, who cares?