One idea: Get her to read the news.
Or find her a bunch of stories about young girls being assaulted, near college campus, etc.... within the last year and email them to her. Maybe she'll think hard about it.
My girlfriend, although half a dozen years older than your daughter, is in about the same boat. (I'm in my 20's too, no pedophilia here.) I try hard to get her to have more situational awareness constantly, but she's not into it.
She gets annoyed with me being "paranoid" all the time (i.e., choosing corner booths in restaurants, crossing the street to avoid a group of shady characters, not using ATMs or getting gas late at night, etc....). She's not anti-gun, but she doesn't have the defensive mindset by any means. I share your frustration.
She won't carry a gun, period. She says she doesn't want to "live in fear", and she doesn't want to hear my argument about it. I did get her a taser and a can of OC, which she keeps in her purse and has probably never practiced using.
I try to convince her that all those stories on the news are real, and it could happen to her.... most younger people seem to have this idea in their head that "it wont happen to me".
It may take a big reality check to get them interested. You, as a parent, have a lot more leverage than I do as a boyfriend though. She's been dropping hints at marriage... Maybe I should make it a condition
Sorry for the rant, but I know how it feels to WANT someone to have more SA, and you can't get through to them.