Are they sure this isn't a matter of people having seen the videos through other means? I've rated movies I saw in theater or dvd in netflix before so that it can know me better. Guess that's a waste of time.
I think their data science people don't really respect the users own ability from what I have heard. If someone is rating a film not seen through your platform, it should be obvious that a) they have seen it elsewhere and b) if its a 1 they dont want to see that again