There is a room in a bunker in Santa Monica, California, with all the windows blacked out. Even if you can charm your way past the security guard stationed outside, you will still need to scan your fingerprint to get in because the information taped to the walls is top secret. Yet this is not a government facility; it is the writers’ room for Amazon’s new TV series – and you’re not getting in.

When news broke of Amazon’s hi-tech anti-spoiler measures for its (as-yet unnamed) Lord of the Rings show, it was met with derision. Chris Ryan, host of the Watch, a pop culture podcast from the film/TV website the Ringer, compared the measures to “working in a failing Soviet state in the 80s”. “Secrecy is such a powerful thing right now,” he said. “I think they’re using [it] to drive interest.” Amazon’s show is, after all, based on an 85-year-old series of books, which have already been adapted into a number of hugely popular feature films. The TV adaptation is rumoured to focus on the character of Aragorn – played in the films by Viggo Mortensen – and is set before The Fellowship of the Ring. The critical consensus was largely that the measures to protect this sacred information were unnecessary. Can anything in that writers’ room really be that much of a spoiler?

Well, in 2019, it feels as if the revelation of even the smallest detail can be claimed to ruin the viewing experience. Is news that there is a new outfit a spoiler? An episode title? A pair of characters meeting? It is hard to say; there has never been a solid definition of what is or isn’t a spoiler – and with dedicated fans willing to scour the internet for any clues from which to extrapolate the plots of their favourite shows, it is getting harder to keep anything undercover.

This year, three of the biggest beasts of on-screen pop culture reach their apex – Game of Thrones, the Star Wars trilogy and Marvel’s sprawling Avengers franchise. In response, anti-spoiler culture has become a whole industry in itself. Self-detonating scripts and anti-drone technology, fake scenes, fake cameos and footage used primarily to misdirect audiences sound like the extreme tactics you would find in a spy movie, but now they are apparently being used behind the scenes to stop unwanted news leaking out.

Fighting spoilers and plot leaks has been par for the course in big studio movies for some time. And HBO and Amazon are beginning to realise something the likes of Disney and Marvel have known for years: secrecy can drive interest, control the narrative more tightly and stave off negativity on social media. Anti-spoiler security may not be strictly necessary for every show, but in 2019, it has also become something of a status symbol.

Fake scenes and fake cameos mean you can’t always trust what’s in front of you. Photograph: HBO

Game of Thrones, whose epic story concludes with its eighth season this month, has been pummelled by spoilers through its run. A 2017 hack saw the scripts for the seventh season leak, revealing nearly every plot twist, death and story beat. HBO affiliates in other countries also accidentally aired two episodes several days early. With the network making headlines for these kinds of mishaps – episodes of seasons five and six had also leaked – and with the final season on the horizon, the production companies were determined to prevent any more crucial storylines leaking out.

Nikolaj Coster-Waldau, who plays Jaime Lannister on the show, told EliteDaily last year about “crazy levels” of secrecy, including digital scripts that cease to function after the filming has stopped: “When you’ve done the scene, it just vanishes.” In another interview, Sophie Turner, who plays Sansa Stark, said that “drone killers” were introduced for filming on set in Northern Ireland – devices that can disable airborne drones and force them to land.

Astonishingly, drones flying over sets – much of Game of Thrones is shot on location – had been used to discover a number of spoilers, and much like the Gatwick fiasco last Christmas, it felt like a problem few had previously considered. Eventually, some of season eight’s scenes were filmed close to Belfast airport – a designated no-drone zone.

One industry insider, who worked on Game of Thrones for several years, but is not involved in the final season, says the stricter controls over information were due to the media ignoring embargos. “The only real change in PR strategy was access to screeners and to the cast, and the changes only came about when there were spoilers or leaks from people breaking the guidelines.” For example, after the season five premiere, which took place at the Tower of London, a detailed description of the first episode was posted to Reddit within hours.

“Game of Thrones just became something of a self-promoting beast. It’s like a Marvel movie, it has its own wide fanbase who will definitely watch the show, and to some extent help you to promote it with teasers or trailers. With that in mind, giving out additional information can be harmful, I’d say, as it takes away from the ‘WTF’ launch night/special episode moments. Some fans genuinely don’t want to know too much before going in; media coverage can be damaging sometimes.” And keeping a tight rein also means that when any information does trickle out – at the creators’ discretion – the media will lap it up.

The final seasons of other big-hitting shows, such as Breaking Bad and Mad Men, had similar levels of hype, but due to remote locations and interior sets, spoilers were relatively hard to come by. Matthew Weiner, Mad Men’s creator, gave nothing away from upcoming seasons of the ad-land drama, telling critics that even revealing the year in which the final season was set would ruin it for viewers (spoiler: it did not).

Drones are a security threat for film units trying to keep their work secret. Photograph: Chris Harris/Alamy Stock Photo/Alamy

The film industry has historically been more wary of spoilers, but it, too, has had to adapt to the way the internet influences conversations about pop culture. For Avengers: Endgame, the sequel to last year’s Infinity War, which, er, spoiler alert, saw more than a few casualties among its A-list cast, similarly extreme steps have been taken. But, this time, it is actors who are being clamped down on, rather than technology.

Robert Downey Jr told Jimmy Kimmel that he was involved in writing fake scenes, while Tom Holland was given a script full of fake scenes due to his apparent propensity to give away plot twists during interviews. (Holland was so untrusted that it was recently revealed he wasn’t even told which character he was fighting in a CGI sequence.) The fear of spoilers carried on beyond production, too: critics at the early screenings were told, “Thanos demands your silence”, a message that became a core part of the social media campaign.

“We can’t trust anybody – least of all Tom Holland – with the truth,” the film’s director, Joe Russo, told Games Radar: “It’s a burden to bear for them. It’s probably easier to have read a fake script and a fake ending because they don’t have the pressure of knowing what happens in the movie, and then they have to hide it.”

In a podcast interview, Karen Gillen, who plays Nebula in the Avengers series, explained that each actor was only given the pages for their own scenes, which, due to the huge ensemble nature of the film, meant there was an awful lot of plot she wasn’t privy to. “The directors would fill us in on everything that we needed in terms of context, but still, I don’t know what this movie’s about,” she said. The subsequent trailers for the mega-blockbuster, out this month, are so vague that the film’s rumoured three-hour runtime has left fans scratching their heads. “I can’t believe they even cut together a trailer,” Chris Evans told the Hollywood Reporter, “because so much of it is a visual spoiler.”

“I think workflow becomes a little more efficient when people aren’t distracted about what’s happening on their cell phones, worrying if something is on the record, or being recorded,” says one industry spokesman. “People are beginning to realise that there are consequences to walking around with a tiny computer in your pocket.”

However, the secrecy parameters of the film studios are different from those of a TV show such as Game of Thrones or Lord of the Rings. Actor contracts form such a huge part of the Hollywood machine that it can be public knowledge how many films an actor has signed up to with a particular franchise. That has been the case for the Avengers films. Coupled with the long lead times for new projects (this year’s hit Captain Marvel was first announced in October 2014), fans can tell a lot about who may be leaving or remaining in the cast simply by looking at whether any sequels are announced. With sequels in the pipeline, it is safe to assume that Holland’s Spider-Man, Chadwick Boseman’s Black Panther and Benedict Cumberbatch’s Doctor Strange will be with us for a little while longer. Evans, meanwhile, has made no secret that his time as Captain America is coming to a close.

Chris Evans as Captain America in Avengers: Endgame. Photograph: Marvel Studios 2019

Actors from older franchises, such as Star Wars, point to how radically things have changed. Mark Hamill told Entertainment Weekly that when he first started out as Luke Skywalker, he was able to show the script to friends. Now the scripts are printed on red paper to make photocopying impossible, and read under supervision. “They’re going to fly [the rewrites] over with somebody from the company,” he said, of the final episode of the trilogy, out at the end of 2019. “They’re going to come and give it to me and wait for me to read it before I give it back … you can’t even keep it overnight. But that’s the way it is now.”

This dance between production companies and fans has been made more competitive by online presences such as the Thrones fansite Watchers On the Wall, which regularly broke the news of casting, filming and inside information on previous seasons long before it was picked up in the national press, thanks to an extensive network of insiders. Yet the site’s editor, Susan Miller, says the big networks have had to learn to “tolerate” this detective work by their fan communities because they are the people who have contributed to the shows’ successes.

“Any fan community, even an annoying one, is good to have,” she says. “The obsession with knowing every detail is an extension of our love for the show. And HBO is too savvy not to know that, and make it work for them.”

However, she argues, leaks, such as those from season seven, don’t affect people’s enjoyment, and anti-spoiler measures are largely a PR exercise. “The only people affected by the mass leaks are the ones who choose to read them, spoiling themselves extensively. And for many, that’s not a problem – they don’t mind not being surprised.”

Thanks to streaming, catchup services and the sheer volume of content being made annually, Game of Thrones – which everyone seems to watch at the same time every week – feels like the last of a dying breed. Newer shows that have become something of a phenomenon – such as Netflix’s Russian Doll or Amazon’s Homecoming – are so short that consumers can devour them in an entire weekend and move on to something else.

So it may be a while before anti-spoiler technology becomes a more regular fixture on television sets – would anyone be up in arms if the True Detective finale was spoiled, for example? Perhaps Amazon hopes that, by kicking off its potentially lucrative new show with the kind of secrecy surrounding Game of Thrones, it can attract sufficient interest. But this clandestine approach can also help prevent one thing that could sting more than a plot twist: total and utter indifference. Perhaps that is what these measures are really designed to protect against.