Knowning that calling her anything related to her height is a death sentence. (Complete with a death glare) You won't hear her say anything and that is scary enough. It would be miracle if she warn you in advance.
Tanya thinks this stupid dance will convince the brass that she has lost her mind and must be taken out of active duty and put in a sanitarium. Rerugen thinks the Devil of the Rhine is deliberately making a fool of herself to show how the brass values her too much to even consider reprimanding her. Zettour, who is off camera, thinks Major Degurechaff is showing a routine she developed to raise morale, and will make it the centerpiece of a propaganda event.
Dumbass question, but how really attractive would Marisa be for the average 19th-century guy in Japan? I would guess she would be deemed as too "eccentric" for the time.