I don’t think a teacher needs to go through that much trouble to identify “lonely” students. They are very easy to spot in the classroom and in the overall school environment.
I might have agreed with you until I was taught how to use statistical analysis in manufacturing production, including the actions of workers. All of us have unconscious biases and blind spots that may keep us from seeing some of the things that, in hindsight, are said to have “fallen through the cracks.”