Considering the thousands of people who work on a film and the many more who are involved in distribution and marketing, it's incredibly difficult to keep spoilers, twists and revelations under wraps.
This is especially true in an age where everyone carries a camera in their pocket and internet access is only a few brief taps away, but even decades ago, information could still leak out via a talkative cast member, well-placed photographer or unnecessarily-detailed advance movie review.
It's not just the fact that the principle of leaking private information is wrong, either, it's the fact that most moviegoers will have a much more enjoyable time at the cinema if they know very little about a film's story.
Movie studios and filmmakers are aware of this, and some of the lengths they've gone to to keep plot details under lock-and-key are unbelievable to discover.
These range from alternate scenes being shot to flat-out lies being told to the general public, and though you're probably aware of the following plot moments by now, you may have one of these oddball methods to thank for your initial spoiler-free cinema experience.