No, that's exactly right zDom. What I was getting at is that the guy really did pick up on something real in Carol's attitude---she really would have fought, she knew it and so did he---however he came by that knowledge.
When a guy starts in on any kind of aggession, the thing he's looking for is a sign of fear in the prospective victim. I don't know how you would test this out, but I suspect that that's especially the case when he's contemplating aggression against a woman. And when instead of showing fear, everything in her response---what she says (or doesn't say), her body language and so on---makes it clear she's willing to do damage to him, it definitely communicates the message that it's time for him to go home. Definitely, it goes beyond appearance, as you say---because if it isn't really there inside, it's not going to convince him.
This is one of the great benefits for women in doing MAs, I think---it gives them that inward sense of power and ferocity that by itself will probably change the mind of the average predatory creep. Those guys are cowards, and a woman who're prepared to hurt them badly is way more than they want to face.
