One would imagine regulations apply differently when not at a starbase.So what happened in the (Kangaroo) Court in Turnabout Intruder? Spock had two on the jury who were below his rank and someone he had conflicts with all the time. And then Kirk/Lester overruled it anyway. I suppose because it was a MUTINY a Starship Captain might have special powers but Chekov said No.
Ah Spock committing mutiny twice although I doubt Turnabout Intruder with Spock's passive resistance would be considered a mutiny by anyone who wasn't insane or some idiot redshirts.