This sounds like a terrible idea to me. With all the Russian bots out there, once they use their forces for evil (labeling real news as fake), all this will do is damage legitimate news. To defeat fake news we need an impartial arbiter to declare it fake. Allowing the users to say what is fake or not is the opposite of what needs to be done. The users are in a bubble. That's how fake news worked in the first place.
