According to the article at http://blog.ifeng.com/article/2737487.html, one of the actors in the film, Carina Lau, was forced to appear in this movie for free. She was the victim of an infamous kidnapping shortly before this movie was made, and later photos of her in distress were published in a magazine, which has since been forced to shut down and its publisher sent to jail. The actress denies she was assaulted but there was a movie leaked on net that allegedly showed her being gang-raped. (The Hong Kong press, out of respect for her, has mostly refused to report on the incident, but google will turn up a few articles about it.)