Our standard for allowing users to rate on a story is very simple: the story must have been published to the platform at least once.
There is no foolproof way to verify that users have actually read the story that they are rating for, or that the rate that they are casting is what they really think about it. We depend on and expect our users to be truthful and only vote on those stories that they have personally read.
We are aware that there are people who may vote for the sole purpose of trying to lower the rating for a movie (this happens both ways -- there are just as many people who try to inflate a vote). We have several safeguards in place to automatically detect and remove this type of ballot stuffing: even though we count all ratings we apply several countermeasures against all attempts to skew the rating.