This isn't a shady grey area; these are legitimate uploads by studios like Paramount, MGM, Lionsgate, and Sony. Because they are official uploads, the quality is usually HD (1080p), and you don't have to worry about the video being taken down halfway through.
YouTube’s Hidden Goldmine: Surprisingly Good Free Movies (If You Know Where to Look)
While YouTube is known for vloggers and music videos, it hosts a massive library of full-length, high-quality movies that are completely free to watch. The catch? You have to know where to look.