Personal story:
In high school chemistry class, I was sitting across a male I was partnered with for the day with our desks pushed together to be facing each other. We were barely acquaintances, but I had no problems with him prior to that day. We discussed the subject matter, discussed things unrelated to the subject matter (mundane subjects like fast food, movies, and the like from my memory).
Suddenly, I felt his hand reach up my skirt, slide up my thigh, and make it's way toward my genitals in a matter of two seconds. He gave no notice, no hesitation, it was a sudden and direct sliding up my thigh toward my genitals.
Instinct took over. I grabbed my chemistry book and hit him across the face, jumped up from my desk, point a finger in his face and yell, "Don't you ever reach up my skirt again *******!!!"
The entire classroom was stunned. I sat back down, the teacher told everybody to stay calm and get back to work, and nothing else was said. The guy across from me never confronted me about it, but I was asked by the teacher after the class was over what happened. I recounted what happened and the teacher shrugged his shoulders and said he was just checking.
I've told the story before many times over the years, and the reactions are mixed. I was told I didn't have to assault the guy by some. Others gave me a "you go, girl" kind of reaction. When asked for my thoughts on it, the only thing I can say is that it was immediate and instinctive. There was no thought in it all. I didn't think how to break it to him gently. I felt assaulted and I immediately felt I should put a stop to it.
So when I saw the video, saw some online commentary to it, it reminded me of the conversations surrounding my own experience.