I ran across this article today: Rape aXe: Putting Teeth Into the Fight Against Rape. It is a new condom-like vaginal device that has barbs on it. If a man rapes a woman, it attaches to his penis and has to be surgically removed, thus enabling identification of the rapist.
It is intended for situations in which rape is endemic. The author troubles this by stating that in conflict situations where gang rape is used as a weapon of war, this is likely to cause more violence for the woman.
It also made me wonder if it is problematic to put the onus on women to prevent rape, rather than working to create cultural conditions in which this violence is not acceptable or thinkable.