Major spoilers ahead. There's a lot going on in Bad Times at the El Royale: violence, guns, an apparently kidnapping, a fake Southern accent, a fake priest, a boatload of cash buried under some floorboards, a cult led by a guy who looks like Chris Hemsworth. But mixed in with all of this are the secret tapes in Bad Times at the El Royale that us viewers don't even get to see.
While El Royale doesn't tell the audience what is on the tapes, there are some clues about their contents. We first learn about the existence of any secret tapes when "Laramie Seymour Sullivan" (Jon Hamm) locates a hidden camera behind a two-way mirror pointing at one of the rooms of the hotel. We also find out that Laramie has been wire-tapping one of the rooms himself, is in the FBI, and is clearly after evidence of something himself.
After Laramie's departure, Father Daniel Flynn (Jeff Bridges) then finds film reels in hotel employee Miles' (Lewis Pullman) room. And he's so interested in what's on them that he steals them and doesn't let anyone know — including his new partner in crime Darlene Sweet (Cynthia Erivo).
When it is revealed by cult leader Billy Lee (Hemsworth) that the "Father" has the tapes, one of his young followers, Boots (Cailee Spaeny), says that she recognizes the man on the film, and it's made clear that he's someone important. Plus, the fact that Father Flynn planed to steal them in the first place — along with his bag of cash — shows that the tapes must have been worth something.
On top of that, there are numerous mentions from Miles about the things he's seen in this hotel and how "management" has had him keep many, many secrets. At the beginning of the movie, we also see photos of El Royale in its heyday on the walls, including celebrities like Marilyn Monroe and the Rat Pack enjoying their time there.
So, to sum up what we have: a hotel that was super popular in the early '60s; interest from a government organization; an important, recognizable man being caught on film in one of the rooms; the film reel being valuable; and a whole lot of secrets. The evidence, and the fact that this movie was set in 1969, point to a politician being caught on camera having an affair and/or doing something sexually explicit, and John F. Kennedy comes to mind in particular.
To be clear, there is no confirmed sex tape of JFK in real life, but it is rumored that he had many extramarital affairs, including one with Monroe, who was pictured as visiting El Royale. And, there was an actual hotel and casino on the border of California and Nevada that El Royale is based on, per The San Francisco Chronicle. It was called Cal-Neva and was frequented by celebrities and the Kennedy family in the '60s. Director Drew Goddard told the publication, "Who knows how true any of the mob stuff and Kennedy rumors are, but it’s titillating to a writer’s imagination."
In 2001 an employee at a re-opened version of the hotel told Salon, "There you see [rooms] 3, 4 and 5. Three was where Marilyn stayed. It had the circular bed, and that's where she got it on with JFK. There's all sorts of catacombs underneath here. When I first started working here I stepped in the wrong place and fell 6 feet through the floor."
This all makes pretty clear that the secret tapes are inspired by Kennedy, but there are some other rumors and reports about the former president that also make him a likely subject. The New York Post reported in a story titled "JFK’s love affair with NYC" that his use of the city's Carlyle Hotel was the stuff of legend:
Kennedy, according to legend, would use the hotel’s warren of underground tunnels to sneak his girlfriends — including Monroe — in and out to avoid detection, leading former bellman Michael O’Connell to famously quip, "Kennedy knew more about the tunnels than I did."
Sounds pretty, El Royale-ish, too, right?
In addition, there is a story about Kennedy and a girlfriend before his marriage, Inga Arvad, who also happened to be a suspected Nazi spy at the time. They once met in a hotel room in South Carolina that had been bugged by the FBI, which was tracking Arvad. The Washington Post reported that "by some accounts" there is a sex tape of the two. Again, this has not been confirmed.
Bad Times at the El Royale purposely doesn't make clear who is on the tape, which makes sense because all the main characters are fictional and it would take viewers out of the story if it did. But still, since much of what happens in the movie is based on real life in the '60s (Darlene's backup singing career, Billy Lee as a Charles Manson-like figure) and Goddard was inspired by the real hotel, it's hardly a stretch to think the tape was meant to be of JFK.