The "relying on one source" is the phoney argument that your typical activist/propagandist/media whore uses when they get caught in an obvious lie. I don't believe for a second that the Urinalists who get caught spreading this kind of crap made a "mistake".

The truth is, the activist/media whore is looking for an opportunity to push their agenda, and will automatically trot out the "relying on one source" excuse whenever caught.

In the paraphrased words of Dan Rather, "Just because the story is based on a lie, doesn't mean it isn't true."