Our absence procedures are no different from those in Rory's school. The same events could have happened with us. To make it worse, I had already spotted the potential for tragedy in our routines and, apart from occasional discussions with our office staff, did nothing to improve them.
Parents assume their children are safe in school. They know that if something goes wrong - usually sickness or injury - the school will contact them. Many will not have known until now of the loophole which applies to the child who simply does not turn up. If he or she is not in class, the school presumes that he or she is legitimately absent and in the care of a parent.
Only where a child has a history of persistent and unexplained absence, or comes from a fraught home situation, will the school contact a parent quickly. The respectable, sensible, well-behaved child, such as Rory was, can be absent for a day with no questions asked.
So the debate begins. Should schools take the initiative in contacting parents over a child's unexplained absence? Yes. Is that what we do in our own school? No. Because it's not as easy as it seems.
At 9am schools can't be certain about the status of absent pupils. The parent may forget to phone, remembering only later in the day. A message may be delayed because a sibling has it and he is still half-asleep at nine o'clock or he's at PE first period. Nor will it be the first time that a parental note has returned home in the bag, undelivered. A child may be late rather than absent, and the child who is absent for one day only may be bringing a note on his return.
Then there are logistics within the school. In the first part of the morning, clerical staff give priority to collecting money, forms and messages, on the grounds that later in the day there is a higher risk of them being lost. They also deal with a large number of telephone calls then, too.
In our school, most parents phone early to explain a child's absence, but even if there is only one unexplained absence per class in a morning, staff would have to be available to make 14 phone calls. Fourteen phone calls is more than I make in a day, perhaps in a week.
Factor in the many parents who change their phone providers regularly yet who forget to tell us of their new number, and you have a major commitment of time and energy. Seasonal flu and chickenpox epidemics would bring extra complications.
Primary schools are not as simple as some people think. The influx of non-teaching classroom staff and additional teachers has led to a more complex organisation, often without corresponding increases in necessary clerical and managerial support. Quite simply, a system of contacting parents each morning requires better resources of staff hours and telecommunications systems.
We've been here before. The ease with which Thomas Hamilton was able to gun down Dunblane pupils almost 10 years ago was not a surprise. Many of us realised that our schools were wide open to any intruder, but no one was really interested in school security then. Lord Cullen's inquiry changed all that, and the resources to improve security were found.
Rory's murder will eventually result in new resources for improving school contact with parents. So often, the system works only in retrospect.
Brian Toner is headteacher of St John's primary in Perth.