This is a very interesting thread.
I always think women are taught to supress their instincts by attempting to be "polite" and to use "linear logic" (ie, "there is no reason to fear that man and you have to give him the benefit of the doubt").
Just for purposes of sharing, I had 3 very distinct incidents in which I became hypervigiliant in regards to men.
1. I went to a private kindergarten art school, and on one day, a man came to give a presentation on fairy tales. I immediately sensed something "creepy" about him, as he would make a point to stare at me or to sit close to me, and I immediately went to one of my teachers (who was probably about 24 years old) and told her I wanted to go home. She couldn't quite understand it, and called my mother to pick me up. I was only about 5 years old then, but looking back, I think he was probably some sort of child molester. According to Bertrand Russell, children are most immediately in touch with their atavistic instincts. I think that young children (and also animals) can immediately tell if a person is dangerous or being insincere.
2. I was 15 and at an outgoing for a camping trip within my church. There was an adult male supervisor there who was visiting from another branch of the church. During the entire weekend, he kept taking numerous photographs of me, while ignoring the other children. I immediately sensed there was something "not quite right" about him and made it a point to be with the other male churchgoers my age during the entire duration of the trip. Anyhow, the boys ended up protecting me, but one of them did end up throwing me into a lake for fun.

However, the male supervisor never approached me while the other boys were around, although he tried very hard to approach me around other girls. The gut feeling (Te + Ni) I had about the man was exactly similar to the incident when I was 5.
3. Just recently, I was picking up some items at a shop, and a man was following me around the entire store. He followed me everywhere and I had the initial instinct to run. But since I was surrounded by people in daylight, I convinced myself that I wasn't in any danger. As I was leaving, he followed me to checkout, then outside to where my car was, but stopped just before the outside of the entrance. I think the reason being was that there were many people around, and he couldn't act without being seen.
I think we should trust our instincts. They are quite logical in that we immediately sense something wrong about the entire picture, and even if we do not have all the evidence, there is something there that threatens our well being.
OT, I felt the same way about John Edwards watching him in the Democratic debates. There's just something about that man that feels "wrong" to me. I'm not comparing him to incidents 1-3, but definitely something about him brings about those atavistic instincts within myself in which tells you not to trust that individual.