Not sure about that.
Does adult content make a source unreliable? Remember this?  It was flagged for adult content on fb, and there was a lot of controversy about how it shouldnt have been removed.
It also checks if there are tweets referenced in the article, and if so, checks to see it actually exists on twitter. What about a hypothetical story about someone saying something controversial on twitter, then deleting it? Is that news? Because that story would be marked as fake since the tweet no longer exists.
Then there is this story. The article "makes it sound like it's looking at arbitrary text and evaluating it for truthfulness". So would this be marked as fake news? Does the wapo domain get added to a blacklist?