I read somewhere that all women are "sensitive"/aware when a man is walking behind them on the street/sidewalk, there's always a very slight feeling of threat since men are bigger/stronger and could overpower us. I would think if you have been raped, that sensitivity and possibility would stay stronger than with a woman who had not. It would be/is a little harder to chalk the feeling up as your imagination or to discredit the possibility of threat when you are alone.