Not only is it not "malpractice," it's perfectly "within the tradition," esp. since the tunes are already first or second cousins.

It would have been academically desirable (for the handful of us who care) if the revivalists had specified their contribution, but they didn't. Let's just be thankful they were governed by such good taste.

Neither did Hugill, who, as a working chanteyman, must have created verses which later appeared anonymously in his books. And he may well have forgotten which ones.