I remember many years ago I was walking home, in the small hours of the morning, through an area it was generally recommended that women didn't walk alone at night. Some said men shouldn't walk alone either, but I'm a big guy and at the time I wore enough black that people told me I looked intimidating even in the daytime, so always figured anyone wanting trouble would pick an easier-looking target. Across the road I was aware of a woman, apparently on her own, using a telephone box (hey, I said this was many years ago!). Shortly afterwards I heard rapid footsteps behind me, so span around to face what I expected to be an approaching threat.
It turned out to be the woman from the phone box. I hadn't recognised her - I'd just clocked "woman in phone box" and nothing more. She recognised me - she lived in the same block as me, and asked if I was heading home and if she could walk with me. It turned out she had made plans to get home from her night out but something had gone wrong with them, leaving her alone and feeling very vulnerable. The look of relief on her face when she realised she wouldn't have to walk home alone was palpable.
When I first noticed a woman out at night, on her own, in an area known to be less than safe, and very shortly after a number of sexual assaults of varying severities had been reported in the immediate area, I have to confess I wondered what she was thinking. As it turned out she had done nothing more silly than go out for the evening with plans to get home safely, but the latter part of her plan fell through and left her vulnerable. It was a good lesson in not assuming what's going on with someone else.
Expecting women to stay inside for their own safety sounds like something from the Stone Age. I'm all for taking responsibility for your own safety but that's just ridiculous. As NerdGirl said, women get attacked in their homes as well.