Obviously, in the literal sense, she's right: Predators tend to prey on women who are alone. Women---and men---shouldn't be totally unaware of their surroundings or act completely without regard for safety, and that includes their personal surroundings.
The trouble is that versions of that argument have been used to restrict women's movements and behavior forever. If she only hadn't gone out alone/worn that dress/had that extra drink/left her drink unattended/forgotten her rape whistle/let herself be alone with him/flirted, she wouldn't have been attacked.
What we tend to forget when making these arguments---some of which, like Bagshaw's, sound perfectly reasonable when considered without that context---is that the only thing that ultimately prevents sexual assaults against women is for men not to assault women. All that energy spent teaching girls and women to constrain their lives and live in fear would be far better spent teaching boys and men not to sexually assault. Unfortunately, we do a very thorough job in our society at the former, and a pretty wretched job at the latter.
Bagshaw says she agrees with the idea of focusing sexual-assault prevention on men, and she may modify her post to reflect that. However, she adds, "women need to protect themselves from those who have serious issues and it has nothing to do with clothes, it has to do with awareness of who is around them."
Unfortunately, in the absence of assault-prevention campaigns that don't rely exclusively on women to avoid being assaulted, self-defense simply isn't enough. And advice like "don't go out at night alone," well-intentioned as it may be, is only a point on the continuum that leads to "she was asking for it."
Or, to quote a few pieces of advice from my favorite list of sexual-assault prevention tactics:
Don’t put drugs in people’s drinks in order to control their behavior.
When you see someone walking by themselves, leave them alone!
USE THE BUDDY SYSTEM! If you are not able to stop yourself from assaulting people, ask a friend to stay with you while you are in public.
Carry a whistle! If you are worried you might assault someone “on accident” you can hand it to the person you are with, so they can blow it if you do.