Flashing in school is not acceptable behavior. It could make others feel uncomfortable or violated. If you witnessed this, you might want to talk to a trusted teacher or counselor. They can handle the situation in a proper way, like having a conversation with the girl to make her understand the inappropriateness of her actions.
Well, if there's a girl flashing at school in a story, it's a very concerning situation. Firstly, it might be a sign of the girl seeking attention in an improper way. However, we also need to consider if there are any underlying issues that are causing her to act this way. Maybe she has some personal problems or misunderstandings about appropriate social behavior. But still, it should not be tolerated in a school setting, and steps need to be taken to address it, like providing her with proper education on social norms and values.