it hones their instincts and gives them confidence at that age and at your DD's age it gives her experience in using her gut to figure out if everything is ok or not. Violence and rape are like when i dog bites, you ALWAYS get some kind of warning, your gut will tell you "uh-oh, problem!" but kids need to learn to listen to that feeling, and apply it even to their own boyfriends if said boyfriend is drunk and acting weird (i'm sure those boys who were groping the drunk girl are NOT all sexual predators, but that youth, booze and her helplessness meant they turned a bit that way).

Teenage girls are usually hypercritical and scathing but it actually protects them well if they recognise a "creep" and turn that distaste on them.

Bx
I don't agree that you ALWAYS get some kind of warning. Often yes but we can't always trust our spidey senses - some people are smooth enough to get around them. In fact I would say that if we're over confident about our instincts we can run into trouble because we assume that if there was a problem our gut would tell us.
Ted Bundy was charming - he charmed his way into the confidence of young women and then killed them. A friend of mine once asked for moral support - he didn't like seeing his father because he had abused family members and friends. I went along for drinks not once but numerous times (it saved him from having to ask other people and explain why). The father was a very approachable and friendly person. Nothing outwardly creepy about him and a pillar of the community. Had I not known what he was I probably would have given him my number and befriended him. I'm not a very sheltered person and I have pretty good spidey senses but this particular guy wouldn't have set them off.
I think that if we emphasise our instincts too much we put children at risk of getting into stupid situations because their senses weren't tripped. Teenage girls in particular are easily convinced of their worldliness yet simultaneously rather innocent. It is a combination that makes them very vunerable.
So yes, encourage them to trust their instinct but temper that with the advice that there are situations they need to avoid regardless of how trustworthy a person my seem and that there are some people who won't set off alarms until it's too late to do anything about it.