When I was at school my form tutor gave everyone her home phone number and hardly anyone rang it.
But we knew that we could, and that built such trust that we actually didn't abuse it. Subsequently I worked as a youth worker and gave my mobile number out to young people. I was worried at first, but actually it was fine - no pranks, just the occasional phone call about an issue or a text about something that had gone well. Sixty per cent of this group of kids were excluded from school and the remainder were at risk of exclusion. I am not advocating the KIPP approach, but the philosophy behind it may have some merit.