Butchy that’s a spectacular twist of what I said. If my DD was inappropriately touched or sexually assaulted (thanks so much for putting that thought in my head this morning. She’s 5.) I’d get fucking arrested.
But it's not. If you wouldn't have a problem with her responding to someone in those circumstances by telling them to FO/DD/KYS, then it's a just a question of where you draw the line.
When I was inappropriately touched at high school, I responded by slapping the little creep upside the head and pushing me off his chair. And then the librarian came and threw him out the library (yay!) Luckily, I was able to do this before I was still bigger than him. It would be a different kettle of fish if someone tried that now. 
The comment about my DD being assaulted or inappropriately touched was not only irrelevant to this thread, since that thankfully didn’t happen to OPs DD, it was really fucking unpleasant.
I now have that thought in my head, while looking at my innocent wee 5 year old. But you made your point. Happy now?
I think you are completely overreacting but the question stands with reference to any woman or girl, would they be wrong to tell someone who inappropriately touches/assaults them to KYC, etc?
And if you say, "no, of course not, it's fine then", then it's a question of when you think it's acceptable to say such a thing. I think it's acceptable to tell someone to KYC/DD/GFY in the situation described in the OP.