How should journalists handle incorrect tweets?

One blogging convention that I really like involves making corrections by striking out mistakes, bolding corrections, and adding a parenthetical note or a footnote explaining the change. But when a journalist makes a mistake on Twitter, is it more ethical to delete the post entirely (thus keeping a mistake from spreading) or is it better to leave the mistake as-is, but post a follow-up correction? Poynter.org ran the other on what to do about tweeted mistakes.

“The fact is that everyone who’s involved in spreading news also needs to be involved in correcting it — and, right now, in helping to figure out how best to do so. That includes the people at Twitter,” she said. “Why not have a ‘correct’ function (like the ‘reply’ and ‘retweet’ functions) that would automatically send a correction to everyone who had retweeted something that contained an error?”