Atrios thinks journalists should expose sources who provide fake information:
Burning sources who mislead you just seems like a nobrainer to me. Aside from punshing someone who aided and abetted your screwup, it also sends a signal to other would-be bullshitters that their attempts may not be consequence free.
I think there's a time and a place for exposing anonymous sources who have abuse a reporter's confidence. I have no way to judge whether this would be a case. There's a big difference, though, between sources who lie, sources who puff, and sources who are mistaken. If a powerful source uses a newspaper to circulate a lie, then it might be appropriate to expose the identity of the source. On the other hand, if the source was puffing his own importance or was otherwise mistaken about a key fact, the journalist should always honor the commitment to the source. It's extremely difficult to distinguish lie from mistake, so for as much I'd like to know who's spreading bad information through the press, I understand that journalists do have to protect their sources.