Truanting and exclusion

The new ideas about stopping truanting and disruptive behaviour in schools are brilliant. You catch the truants and send them back to school, so they can be excluded for their disruptive behaviour.
Who are more troublesome to society, children who have been excluded or children who are playing truant? How do you tell the difference? Who create more of a problem for their parents? Willl any of them go back to school in a receptive and productive frame of mind? What on earth is gained by all this?