If the instructor shows the incorrect footwork is this correct?I think not.Correct foot work is correct footwork.Incorrect footwork is not correct footwork.
Which is the correct footwork? The feet pointing out style of Yoshinkan? The hanmi in the official works published by the Aikikai? The hanmi of Saito? The shizentai of Nishio? Once we establish this, we can start telling people to ignore their sensei.