I know of a counterexample from this week. The original submitter (I) posted an article I learned about from a local scientist with the original title
http://news.ycombinator.com/item?id=2813270
and then during the subsequent discussion the HN title of the thread was changed to something that I don't think is a fair summary of the submitted article. (I don't know which curator did that, or which users flagged the thread, but I saw it happen after it was too late to edit the original submission.)
The original article is here and you can see its title:
http://independentsciencenews.org/news/23andme-disproves-its...
After edit: In view of the blanket policy statement to which I am responding, I'm especially curious about the recent exception I linked to.