Attempting to make the events that inspire a film sound as credible as possible is a dangerous gambit.
No film is ever a 100% accurate retelling of the story it is based on, as the filmmakers will always use their creative license in order to make events appear as dramatic or impactful as possible, and increase the appeal of the story.
That being said, there are films which market themselves as being either "based on" or, "inspired by" events or stories that the production will insist genuinely happened purely for the sake of marketing and generating as much interest in the film as possible, only for them to be thoroughly debunked either before or after release.
Obviously, even the most heinous of lies can still generate a good amount of publicity and attention (even if it is for the wrong reasons), but then there are also some cases where due to a few throwaway comments, audiences can be led to believe that a film's backstory or inspiration really happened, when it actually didn't...
10. Eli Roth Thought Tortuing Tourists Really Happened
Director Eli Roth literally came up with the idea for this backpacker-slasher whilst swimming in Quentin Tarantino's pool.
According to Roth, he stumbled across a Thai murder vacation website (as you do), where customers would pay to kill and murder people, with money being given to the victim's families in exchange for their suffering.
Roth originally wanted to make the film into a documentary but thought the risks involved with getting in touch with the people who ran the website would be too dangerous and so opted to make Hostel instead.
Except it wasn't too dangerous because the website was a hoax and torture camps for tourists don't actually exist in Thailand.
Roth got into a lot of trouble for marketing the film as being inspired by true events as the production was actually filmed and set in both the Czech Republic and Slovakia, sparking outrage at the way it portrayed life in the two eastern European countries and seemingly encouraging viewers to believe the events they were watching actually happened there.
Roth himself has admitted that even if the story wasn't true it didn't matter because the premise behind it was too good to pass up.