Case in point: the Politico and Huffington Post articles today blasting Gov. Rick Perry's "Texas-sized gaffe" when he said the city of Juarez was the most dangerous city in America, when it's actually in Mexico.
I was at the press conference, and I was interested in Perry's answer on border security, not on catching what was clearly a slip of the moment and nothing indicative of Perry being uninformed. It was a pretty low-key deal; at the end of the press conference, a staffer pointed the mistake out to Perry, and he told reporters that he previously misspoke. At most it probably merited an aside in a story, particularly if you used the quote. It certainly didn't warrant an entire news story to itself with the headline, "Texas-sized gaffe: Rick Perry says Juarez is 'in America.'"
It's also interesting to note that none of the reporters who thought it big enough of a deal to make a story out of it called him out at the time in the press conference. Reporters usually aren't scared to speak up if they think something needs to be clarified.
Journalists aren't supposed to make mountains out of molehills. But I guess even journalists make gaffes, right?