Sexual abuse, assault, and rape are ONLY ever the fault of the abuser, assaulter, or rapist. It is never the victim's fault.
Blaming these crimes on the women they hurt because of "promiscuous dressing" is probably the single most passive-agressive way that people (mostly men) can think of to deny personal responsibility for one's actions. I can't think of any other crime (besides sex crimes) where people try to spin it as the victim's fault. That's just madness.
True, a woman may be able to reduce her risk of rape or sexual assault, but not so much through her clothing. Wearing a halter-top isn't going to put you at nearly as much risk as, say, wearing a halter-top as you walk alone in a dark alley in a large inner-city at two in the morning, drunk as a skunk.
If a woman wanted to significantly reduce her risk, she should be more concerned about where she is, what time it is, who she's with, whether or not she can trust the people she's with, and how alert (sober) she is.
But even still, lowering risk is not the same as prevention--just like having an alarm system doesn't mean your house cannot be robbed. Sometimes terrible things happen to good people. Nobody is 100% safe from mongrels who would sexually abuse a woman--even if she's wearing full-body sweats at a Denny's at 8am on a Sunday.
So no victim should ever blame herself (or be blamed by others) for the vile actions of her abuser.