Based on a current craze for videoing assualts on strangers using a mobile phone a whole new craze opens up. All you need is a bit of bottle, a state of the art phone. And a uniformed policewoman.
John has discovered utility theory and evolutionary psychology, and he's discarding quaint old definitions of morality. He meets a young woman on a hike in the woods and decides that raping her really is the way to maximize his personal utility.