So, I recently re-watched The Motion Picture, and something bothered me that hadn't before. When Kirk arrives on the Enterprise bridge for the first time, all his buddies (and at least one of Decker's buddies) know that he's taking command, but Decker is in Engineering and hasn't been told. Whatever the fictional excuse for his ignorance, the dramatic reason is clearly for a tense scene where Kirk himself has to break the news to an unsuspecting Decker. But it seems to me like a casually unprofessional way for Starfleet to handle a change of command. The commanding officer isn't the first one privately informed, before any of his subordinates? Or is there some reasonable excuse I'm missing for the whole bridge crew to know what's become of Decker's command before he does?