 Because of the illegality of sex work in many parts of the world, sex workers often have to service clients in discreet and isolated spaces where they are less likely to get caught by the police.Because of this isolation, sex workers are made more vulnerable to attacks by their clients.According to a study conducted on one hundred and thirty people working in San Francisco as street sex workers, 82% had been physically assaulted, 83% had been threatened with a weapon and 68% had been raped while working as prostitutes.