I added south-korean and north-korean to What, if any, are the primary differences between Korean as spoken in the North and that spoken in the South? since they seemed relevant.
However, the former tag was immediately used on this question: What are the differences between 는 / 은 and 가 / 이? However, that question doesn't seem to indicate in any other way that answers should be SK-specific, and it's probably not useful to exclude any information relevant to other dialects. I suspect that the tag was used in lieu of simply korean since that does not exist, and the asker is unaware that such a tag would not be useful.
So are these two tags useful, or just confusing? I foresee a lot of similar misuse, but I think they are still useful categories.