Fake is in the eye of the beholder..
The main problem is that everyone is talking about "fake news" as if the definition is all out clear, but truth of the matter is that context and perspective are equally important to determine if something is fake, bended or maybe true yet misunderstood.
And then we also have things such as half-truths, politicians love those; simply don't tell the full story so that you're not lying but... in the very sense of the word also not very honest either.
Seriously though, this shouldn't be the problem of the carrier. Nor should those outlets try to make it theirs because that can only lead to one simple outcome: censorship.
Who cares if news is fake or not? If people would stop being so gullible and taking the easy way out then it would be a lot harder to sell this fake news nonsense. Because that's what it is. And even if your news organization is mostly reliable then that by itself is no guarantee that everything you share will be fully true or on par with general perception. I mean... I still remember El Reg carrying that story about how some vague research institute had determined that Microsoft Explorer users had a general lower IQ than Firefox users. Of course within 2 weeks the story got debunked as nonsense, but in the mean time several outlets had carried it and even more funny: several people heavily defended it too.
But yeah, as long as people don't bother themselves to dig a little deeper into what's real and what's "tainted" then nothing really changes. And that's not even touching the issue of opinionated articles.