I disagree. We must treat every anonymous source as if it has that reputation for lying, as otherwise a source can simply become anonymous to improve the credibility of their lies.

Until, of course, a source presents evidence, at which point we evaluate the credibility of the evidence instead of the source.

Not really...

Even taking all emotion out of it, a story from a source that is probably a lie convey s more emotion than a story from a completely unknown source.