If you weren't aware of it at the time, there was a huge online war spanning multiple web sites over a woman's assertion that being propositioned in an elevator at 3 a.m. was "creepy" and that guys should stop hitting on all the women at atheist conferences. [Ironically she had earlier given a talk on this subject and this guy knew that. He also heard her say she was tired and headed to her room.] Many men argued that this was oppressive and insulting to assume all men are potential rapists. Women and some male allies pointed out that the guy wasn't called a rapist, just that it is creepy to be vulnerable and alone with a man in an elevator especially at that time of day etc. Guys wanted to uphold the principle that it is absolutely fine for men to ask women out anywhere and everywhere and women shouldn't assume the worst. Much density, defensiveness, and misogyny ensued. I won't rehash it all here.
However, I do offer this as a data point as to why women have to be on guard with any man they don't know when they are alone and vulnerable, and even men we do know.
Sorry, guys, the rapists don't come with a handy R tattoo on their forehead so we know to be on guard or to have a protective friend ride in the ambulance with us to fend off our paramedic who is supposed to be helping us, not raping us.