Care system must protect pupils at risk
But how far can schools and teachers be expected to go to help stem the growth in illegal child trafficking?
Teaching staff can keep an eye on absent pupils whom they believe could be at risk. But shouldn't the immigration services and social services be the ones on the ball?
It is likely that a child who is suddenly lost to the education system has had contact with a social worker or immigration officer. They might already be in the care system. So how do these children slip through these books, let alone a school register?
Of course, there could also be dozens of children who can never be accounted for because they were being brought into the country illegally, something found to be happening in ferry passages between Irish and Welsh ports.
It is accepted that better communication is needed between social services, the immigration service and schools. Joyce Watson AM, chair of the new Assembly committee looking into the trafficking of women and children, is keen that schools do more to monitor pupils at risk and keep better records.
Cardiff has also led the way in issuing the first paper protocols on child trafficking, placing greater emphasis on the role of schools. Simon Jones, from children's charity the NSPCC Cymru, is keen to drive the key role schools have in identifying a trafficked child.
At present, no one knows the full extent of this crime in Wales. The work of Ms Watson's committee may reveal more in the future. But schools and teachers can only do so much in the meantime. The responsibility to keep track of these children must surely lie with professionals who work with children outside the classroom - not in it.