The Q&A forum type is creating some SEO issues for us as well. I recently reported the schema markup here, and now I just discovered that the "?order=vote_score" is causing duplicate content. I hope the dev team can look into this and help fix these issues.
@Anatoliy Not at all. Technically speaking, that would be the alternative, but seen too many times that things still get indexed by Google even when I put a rule in the robots.txt. The ultimate solution is nofollow.