After discovering that the character "Officer Obie" was modeled after him, actual Stockbridge (Massachusetts) Sheriff William Obanhein demanded that he play the role himself. His reason: "If anyone is going to make a fool out of me, it might as well be me!"
The real Alice Brock and Ray Brock appear as extras in the film. In the scene where "Ray" is putting up insulation, she is wearing a brown turtleneck and has her hair in a ponytail. In the Thanksgiving scene she wears a bright pink satin blouse. In the party scene she's wearing a Western-style dress.
Although many people regarded Arlo Guthrie's recording of "The Alice's Restaurant Massacree" to be fiction, Arthur Penn, who owns a home in Stockbridge where the story takes place, realized it was for the most part based on events that had actually taken place. Therefore, what appears to be a continuity problem is in fact a correct representation of the facts. The movie portrays the actual photos used as evidence at the trial. The real life "blind judge" in Guthrie's song, "Judge James Hannon," also plays himself (James Hannon) in the film.
Arlo Guthrie's co-defendant in the littering incident actually was named Richard J. Robbins, a 19-year-old from Poughkeepsie, N.Y. (Guthrie was 18 at the time).
The real Alice Brock turned down the chance to play herself in the film. She wasn't a professional actress and felt that there was no reason to recreate for film what she had already done in real life.