Towards the end of the novel, Cordelia uses her "old Ship Captain's voice" on Kou and Drou to make them quiet and obedient. Although the scene as a whole is great, and yeah OK, those two were conditioned to obey voices of authority, Cordelia was a "Ship Captain" on the Betan Expeditionary Force. Using the Voice of Command on her former subordinates would have lead to a prolonged debate and then a vote.
They were still a professional service, and knew when it was time to just follow orders. As Miles tells Elena, describing Betans in The Warrior's Apprentice: "Depends on what you mean by free. They put up with rules we'd never tolerate at home. You should see everyone fall into place during a power outage drill, or a sandstorm alarm."
Yes, but in other places it's made pretty clear that trying to get them to do something "because I said so" was setting yourself up for a long argument.
This troper's father was a naval officer. The whole family knew when one could argue, and when he meant "Do It Now," and one did. Probably because he only used that voice when it was genuinely, urgently important that something be done now, no time to argue.
And indeed, the situation that makes this typical among naval folk would still apply to the Betan Expeditionary Survey: you're all in a man-made vessel that is the only thing protecting you from a large and very hostile environment, so in an emergency everyone had better jump. And in the right direction too.
Indeed, that's kind of the Fridge Brilliance of the whole thing— Cordelia's command voice had to be particularly good, because when it did come time to use it she had to short-circuit her audience's tendency toward debate.
It must also be noted that:
(a) The 'prolonged debate and then a vote' happens in the context of the Betan Astronomical Survey (of which she was Commander), not the Expeditionary Force. The Survey folks make blind jumps for a salary, pension and benefits, so they were all at least a little crazy. The Expeditionary Force... well, they were helping Escobar fight of a bunch of bloodthirsty, mutie-hating, mother-raping Barrayarans. Whoever transferred across probably had to Grow the Beard .
(b) Both Kou and Drou have seen Captain Cordelia Naismith do some wild and woolly things. Kou has seen her face down some Barrayaran mutineers, and Drou was with her when she had Bothari chop off Vordarian's head. She could have used her 'Mother of Miles' voice and they would still have jumped.
Being "Mother of Miles" probably requires a Ship Captain Voice 24/7. This is Miles we're talking about, after all.