How do non-players know this? WotC isn't even putting a sticker on the boxed sets saying "Explore more of the world as seen in Dungeons & Dragons: Honor Among Thieves!"
Only existing customers would know there's even a remote connection.
And it is remote: "OK, sail for a week southwest from Neverwinter, which you saw in the movie. That island out there? That's this boxed set. Oh, and there's some characters who cameoed in the movie in the art, although they don't actually appear in the adventure. No, we don't understand that part, either."