At the start of I Still Know What You Did Last Summer, Julie and her friends win a trip to the Bahamas by answering a question in a radio contest incorrectly—this was a detail that the majority of the movie's audience missed. Cleverly placed, the clue was supposed to be an early sign of danger for the audience, but for most viewers, it went right over their heads.
The film picks up one year after the events of I Know What You Did Last Summer. At the start of the movie, Julie James (Jennifer Love Hewitt) and her best friend Karla (Brandy) win a trip for four to the Bahamas after answering a quiz question for a radio contest. From there, the group sets off to the Tower Bay resort expecting a tropical vacation, but the friends soon discover the terror from last summer is far from over.
What most viewers didn't realize is that the movie revealed something is massively wrong just 15 minutes in. During the radio quiz, the host asks the girls, "What is the capital of Brazil?" The two desperately scramble for ideas, and after fumbling around for a few seconds, they finally answer, "Rio." The radio host tells them they answered correctly and have just won a vacation to the Bahamas. Rio, however, is not the capital of Brazil—Brasília is.
In their review of the film, Variety even stated, "For those who were sleeping in geography class, this exchange will seem rather ordinary. But for viewers who know the correct answer is Brasilia, it’s the first indication of imminent doom." And while the movie briefly references the false radio answer halfway through, it isn't' until the last third of the film that audiences finally discover that Rio was an incorrect answer, and the whole trip was a set-up by the killer.
The writers surely knew that most audiences wouldn't know the capital of Brazil, since Brasília is a city that's hardly known outside of the country. Instead, the moment was an Easter egg for viewers who knew the Brazilian capital, giving them a heads up from the start that the entire vacation was a set-up. Interestingly, this is a common mistake. Brasilia became the capital of Brazil in 1960; Rio de Janeiro was the capital for many years before this change was implemented. An easy mistake to make, and one that the filmmakers were likely intending to capitalize on to play an interesting sort of game with their own audience; if the audience guessed wrong, it added a layer of realism to Julie and Karla's wrong answer. For them, there was no wrong answer—it was all meant to be a trap—but it goes to show the lengths the killer was willing to take to get them to the Bahamas.
Whether someone knows the capital—and therefore, the correct answer—or not, the plot device was brilliant. For some audience members, it provided an early red flag, giving them a clue that most viewers missed. For those who didn't know the correct answer, they were able to discover the twist ending alongside the characters at the end of the film. I Still Know What You Did Last Summer has since developed a cult following, and is also credited with being one of the first slasher films to feature a Black final girl.