Over the weekend, the movie Ready Player One opened. The movie is a smorgasbord of references to films, TV shows, games and toys; and each of those references had to be cleared for use in the the movie.
Clearing all of those references might have been impossible, but the movie had an ace in the hole -- Steven Spielberg. His presence helped Warner Brothers clear the rights to a lot of intellectual property, and eventually they cleared about 80% of the material they wanted (see link to LA Times article).
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