I know that from the days of Watergate and "All the President's Men", the notion of two sources on a story has become the popular dogma about how you confirm something. And there is a lot of truth to that, but there are all kinds of ways to check to the extent that you can, a story that you get. And even in "All the President's Men" you may remember the scene where they have a guy on the phone and they say 'Alright, we'll count down to 10, you know from 10 to zero and if you don't hear otherwise then, whatever.
The trouble with that reference, is that some of us, including me, actually read "All the President's Men". Not to mention that I lived through that time in history, and actually know what happened.
And, in fact, when Woodward/Bernstein tried the phone countdown trick, it bit them in the butt - it caused a mis-understanding, and led to one of the few stories that was challenged on the facts - just like this recent story.
Some MSM guys never learn.