Can someone put the brakes on tweeting by some journalists?
Let me remind people: it is NOT journalism to repeat a rumor on a 140 character tweet and, in posting it, say that he or she does not believe it. You don't get off the hook to lame rumor mongering by including in the tweet that you don't believe it. That is flat out spreading a rumor -- not journalism! What this "here it is but I don't believe it" does is put that rumor out there for others to spread! (and yes, it does get spread !)
Incidentally, the above is not a hypothetical.
Instead of tweeting a rumor, the journalist (above) should have done something old fashion: investigate and corroborate....see if it is true...check it out....don't spread a bad story until the journalist has investigated. That is not only journalism but decency.
Sometimes the mere existence of a rumor (a known false story) becomes a story and journalists need to decide, in good faith, whether to report the existence of the rumor or not. It might be newsworthy for instance that someone is on a campaign to smear another. Whether to report or not can be a close call since you don't want to highlight rumors but you also want to make it known, if it is false, that it is false.
And if the fact of the existence of a rumor itself becomes a story, a journalist should not use 140 characters in a tweet to stamp it out. A journalist should use the large platform available to journalists, the media megaphone, to call out those who are spreading it and to correct the rumors.