I’ve checked on snapshot (which by now has the updated version of mod-course) and it looks like it does the right thing: courses that have instructors can be deleted just fine, presumably because the back-end has deleted their instructions as part of that operation. (If we’re being pedantic: we delete the course in the UI, but that also has the effect of deleting the course-listing if there are no remaining courses cross-listed with it, and the instructors associated with that course-listing are then deleted.)

So I think this is all good and can be closed as done.

I have reassigned back to , who did the work, so he can have the honour of closing the issue.