A friend told me a story about being at a party in high school where a young drunk woman was in a bedroom and men were going in to rape her one after the other. This man didn't say anything because he feared he'd be harmed by the other men if he tried to intervene. Men don't often intervene when violent men are hurting others. Maybe sometimes, but it probably depends on how big and how violent and how numerous the perpetrators are... That said, I do feel safer walking with a man at night than walking alone--not because I think he will protect me, but because other men are more inclined to leave me alone.