Many “whodunit” movies are filled with twists that keep the audience guessing who the villains or “bad guys” are in the film. However, now there might be an easy cheat for you to find out exactly who is playing the good guy(s) and the bad guy(s). To spot this, all you have to do is look at the kind of smartphone they are holding in the film. If it is an Apple iPhone, chances are, they are the good guy.
How do we know this? Well…
Filmmaking Secrets Exposed

Rian Johnson, who was the writer and director for the movie Knives Out, let out a few spoilers in a video for Vanity Fair. He mentions that Apple doesn’t allow villains in movies to use iPhone devices on camera. This is a huge spoiler for all filmmakers because it is now easier to spot who will be the bad guy if it isn’t already made clear.
Apple and Their Product Placement
Apple is a company that is big on product placement, especially in movies and television shows. The company uses this marketing strategy to promote its brand. Apple has an employee whose job it is to work with various Hollywood filmmakers and on productions to get MacBooks and iPhones in the hands of the characters acting on screen. However, the key to this role is only to target the good guys in the films.

Apple products are popular all around, and it is common for people to have them. This means that the lack of one in a film can be a legitimate spoiler in a murder mystery movie or any movie with a villain. The company is not open to discussing its product placement rules and specifics, so the revelation from Rian Johnson is a huge spoiler for the Apple brand.