Earlier I'd flagged a question that was tagged untagged, which has been fixed. However, there are still questions tagged as such... I'm reasonably certain that this is not a tag we'd want to encourage. Could these be re-tagged and the untagged tag blacklisted?
Could these be re-tagged and the untagged tag blacklisted?
untagged cannot be black-listed because it is the tag that is automatically added to a question when a tag is removed, and that tag is the only one used from the question. This happens because a tag that is used from just a question is deleted after 30, or 60 days. untagged is also used when a moderator of another site migrates a question on EL&U, and that question doesn't use any tag used on EL&U; as the tags that don't exist in the site where the question is being migrated are deleted, untagged replaces those tags, when the question ends with no tags. (A question always needs to have at least a tag.)
Instead of flagging the question, you could have found a pertinent tag for that question, and suggested an edit. As far as I remember, suggesting an edit to add a tag, or replace a tag is allowed.