At this point, thinking or acting out cute things causes such a powerful fated overhearing/intrusion effect that the admiral should start figuring out ways to weaponize it.
Maybe when they have a tough battle ahead, have the sisters of the participating ships in a room with nekomimi to try on in case their sisters start getting damaged so that they would instantly teleport back to base to catch them going "nyaa~"?
Here I go!Don't I just♪I would swim the world's oceans together with all the fish...Yes, if I was a mermaid,Dechi.MEYou sure think of some interesting things, don't you?If I were to sing, then I'd be a siren too...You said it out loud, you know.It's so nice how good submarines are at diving...Oh, if I were a mermaid...Lalalaa♪