Statistical precedent?
I have been in that situation as a statistician moonlighting in psychology. I have seen my fair share of voodoo statistics here. (Sadly enough, the original manuscript title did not make it into the final article.)

My opinion is that prior errors do not justify later errors. I call out statistical errors and insist they be fixed, no matter how many authors have made the same error before.

Yes, I see the point that then new results cannot be compared to previous ones. But then, how reliable or useful were those previous results, anyway? Standing on the shoulders of giants is not overly useful if those giants are walking in the wrong direction.

It is always useful to refer to published work on specific errors if this exists - especially published work in venues that cater to the specific field. Psychologists will trust a statistical exposition more if it comes from a psychological journal, rather than JASA. I have lost count of how often I have referred to Miller &amp; Chapman's "Misunderstanding Analysis of Covariance" (2001). Statistics in Medicine also often has articles that explain particular misconceptions. If there is nothing in article form, I sometimes include links to CrossValidated.