The Irish government banned the film thinking it might encourage "anarchic tendencies". The ban was only lifted in 2000.
Early in the movie, The Marx Brothers - playing stowaways concealed in barrels - harmonize unseen while performing the popular song 'Sweet Adeline,' which is traditionally performed with four singers. It is debated whether Harpo Marx' singing voice was used in the soundtrack. There is also an unconfirmed rumor that he provided the puppet master's voice in the Punch and Judy show.
According to Robert Osborne, during the first day of shooting, it's reported that The Marx Brothers showed up in each other's clothing and impersonated each other.
Sam Marx: The Marx Brothers' father is sitting on the crates behind them after they're carried off the ship.