Simon and Hawkwood -- I do agree with both of you -- an instructor shouldn't be teaching a "specialty" unless that instructor is actually comfortable with that type of diving.
Simon -- re self-certifying as a "Wreck Specialty Instructor." IF the OWSI has lots of wreck experience, including penetration training and experience, then you'd agree self-certifying is OK, correct? OTOH, do you not also agree that if the OWSI has only 120 total dives, with 10 dives on "simple" swim around/swim through wrecks, then even having taken a "Wreck Instructor Specialty Course" is unlikely to have given the person the skill level necessary to actually teach the course?
If you do agree, then isn't the answer, "it depends" on the experience, and experiences, of the instructor whether he should self-certify?
BTW, I did self-certify as a Wreck Specialty Instructor and I have never done any serious wreck penetration -- never run a line in a wreck. I also will refuse to do any Wreck Penetration in a Wreck Specialty Class and if that is what the student wants, I hand him off to another instructor who has a long course set up for that. Is that wrong do you think?