Yeah, not even Violinist of Hameln pulled that one. (They did have one character who wore a half-face mask all the time so that they could get away with not animating her lip movements as even a simple flap, and I think I remember several conversations where the speaker was deliberately shot from behind.)

Of course, there’s no way Zenshu has VoH’s extreme budgetary constraints, where they literally had to make 1 ep’s worth of funding cover 2 eps of footage.