During filming in 1983, Czechoslovakia was under Communist rule. The production team was often followed around by the secret police, and Milos Forman and the cast spoke about their fears that a Fourth of July prank-the unfurling of the American flag in the concert hall and the singing of "The Star-Spangled Banner" by the large cast and crew-would lead to their arrests for inciting rebellion. Many suspected that their hotel rooms had been bugged during the six months they spent filming the movie.Forman, who was considered a traitor for becoming an American citizen and not returning to the Soviet-controlled area, had previously had one of his movies banned in the country (then called the Czech Socialist Republic). According to Twyla Tharp, in order to shoot in red territory, Forman had to make certain concessions. "Milos had to sign an agreement that he would go to his hotel every night for the year that he was there and that his driver would be his best friend from the old days," Tharp told The Hollywood Reporter. "And everybody knew what would happen to his best friend if something untoward politically happened around Milos, because Milos was a sort of local hero and he was dangerous to the authorities."