Several rumors and misconceptions have grown up around the film, one being that Ronald Reagan was originally chosen to play Rick. This originates in a press release issued by the studio early on in the film's development, but by that time the studio already knew that he was going into the Army, and he was never seriously considered. George Raft claimed that he had turned down the lead role. Studio records make clear, however, that Wallis was committed to Bogart from the start.
Another well-known story is that the actors did not know until the last day of shooting how the film was to end. The original play (set entirely in the cafe) ended with Rick sending Ilsa and Laszlo to the airport. During scriptwriting, the possibility was discussed of Laszlo being killed in Casablanca, allowing Rick and Ilsa to leave together, but as Casey Robinson wrote to Hal Wallis before filming began, the ending of the film "set up for a swell twist when Rick sends her away on the plane with Laszlo. For now, in doing so, he is not just solving a love triangle. He is forcing the girl to live up to the idealism of her nature, forcing her to carry on with the work that in these days is far more important than the love of two little people." It was certainly impossible for Ilsa to leave Laszlo for Rick, as the production code forbade showing a woman leaving her husband for another man. The concern was not whether Ilsa would leave with Laszlo, but how this result could be engineered. The problem was solved when the Epstein brothers, Julius and Philip, were driving down Sunset Boulevard and stopped for the light at Beverly Glen. At that instant the identical twins turned to each other and simultaneously cried out, "Round up the usual suspects!" By the time they had driven past Fairfax and the Cahuenga Pass and through the Warner Brothers studio's portals at Burbank, in the words of Julius Epstein, "the idea for the farewell scene between a tearful Bergman and a suddenly noble Bogart" had been formed and all the problems of the ending had been solved.
The confusion was probably caused by Bergman's later statement that she did not know which man she was meant to be in love with. While rewrites did occur during the filming, Aljean Harmetz's examination of the scripts has shown that many of the key scenes were shot after Bergman knew how the film would end; any confusion was, in critic Roger Ebert's words, "emotional", not "factual".