@gollum,
I think there are only certain news stories in which Fact Check is applicable. If a speaker says that such a law is unconstitutional, Google might have some people with legal knowledge check to see if there are Supreme Court decisions favoring or opposing that law. That's fact check.
On the other hand, if six witnesses see and a video shows somebody walk up to his neighbor and hit him in the head with a shovel, that news story would not be Fact Checked, since the facts are not in question.