Regardless of the legal status of torrenting a movie you already own, to the companies monitoring swarms, someone downloading and sharing a movie that they own

Regardless of the legal status of torrenting a movie you already own, to the companies monitoring swarms, someone downloading and sharing a movie that they own looks no different than someone that doesn't own the movie. You'll still need to respond to their notice if they send it, and possibly defend yourself in court. Even if you succeed, it can be a big burden.