If you're a news organization, credibility is everything.
It's your reputation, your standing in the community, even your bread-and-butter as your advertisers will not want to do business with you if you are not a credible source of information.
To that end, it's very important to check the facts before sending a story to print, putting it on a web site, or broadcasting it over the airwaves.
And even then, you're bound to make a mistake. It's not just a matter of IF, it's WHEN, because it will happen. And when it does, it's also important to correct that mistake.