A bizarre Marvel Studios rule says that Sebastian Stan's appearance as Bucky Barnes in Captain America: Civil War is considered a cameo. Following his debut in 2011's Captain America: The First Avenger, Bucky became instrumental in the overall arc of Steve Rogers, aka Captain America (Chris Evans), throughout his time in the massive superhero franchise. Though he started out as a supporting figure in Steve's story, Bucky has since stepped into the spotlight for his own Disney+ series The Falcon and the Winter Soldier opposite Anthony Mackie's Sam Wilson.
It was in 2016's Captain America: Civil War where Bucky truly seemed to come into his own as he became the key to Steve's true moral compass as a defender of freedom and as a loyal friend. Following the death of the Wakandan king, T'Chaka (John Kani), law enforcement, the Avengers, and Black Panther (Chadwick Boseman) were hot on Bucky's trail as they assumed he was the culprit. Bucky spent much of his time in Captain America: Civil War as an unfortunate fugitive, but he also reached a major turning point in his fight against Hydra's Winter Soldier brainwashing. Stan was a pivotal member of the Civil War cast.
However, per THR, a Marvel Studios rule says that Stan's crucial role in Captain America: Civil War amounted to a cameo appearance. According to this rule, if a character's screen time results in less than fifteen percent of the film's total runtime, then the actor's role will be considered a cameo. Stan's total screen time in Captain America: Civil War was only 22 minutes, meaning that his appearance constitutes a cameo per Marvel Studios' rules. This is essentially so Marvel can limit what it pays comics creators.
A corporate entity such as Marvel Studios having a rule designating the status of roles for its actors is not unsurprising, as such regulations help dictate pay. Hollywood is well known for their intricate loop holes to keep money with the studio and its executives, and Marvel is especially notorious when it comes to poorly compensating the comics professionals who create their most popular characters. In the case of Bucky and Civil War, despite playing a key part in the plot, his status as a supposed cameo likely resulted in diminished profits for certain creatives.
Captain America: Civil War proved to be one of the MCU's biggest hits, with much of its success hinging on the integral performance of Stan as Bucky/the Winter Soldier. This cameo rule from Marvel Studios is humorous as one begins to consider the limited screen time actors accrued in the ensemble film Avengers: Infinity War. The movie was written in such a way that the story was divided amongst multiple leading characters throughout its two and a half hour runtime. The majority of Avengers: Infinity War's stars can thus be considered cameo appearances in a film about Thanos, who ultimately commanded most of the movie's runtime.
Source: THR
