Sorry cm, I actually mostly agreed with your post. That was the only part I wanted to address.
Makes sense. In a perfect and understanding world your approach might have merit "But" both party's have to be rational.
It just seems that everyone has a short fuse these days.
That said, the girl was out of line simple as that. Rules were not adhered to. She was asked by more than 1 person to leave the room. She was disrupting the class.
At what point does this become a serious issue.
It is not relevant in today's world but that would fly maybe 20 seconds when I went to school.