If such acts cannot be anticipated, potential victims have to be protected as far as is feasible. That is why an important part of Lord Cullen's report deals with school security. As was said in the immediate aftermath of Dunblane it is as undesirable as it is impractical to turn schools into fortresses. But most premises have allowed too easy access - for the best reasons. How headteachers and education authorities provide better security will depend on the size, nature and location of schools - and on how far the Government promise of specific grants matches need when it comes through next year.
But security is not just a matter of locks and cameras. The threats to children extend far beyond armed attack. Schools need to define safety in many ways. Drug peddlers and violent bullies far outnumber murderers, and make a mockery of the notion that school is a safety zone. So protection has to be moral as well as physical, and that should fall within the remit of Cullen's "safety strategy".
The danger to children from adults is one of the darker aspects of society. Thomas Hamilton got away with running dubious clubs for boys because his claims and his apparent commitment outweighed the suspicions. Getting people to volunteer their spare time on behalf of others is often so difficult that willingness is adequate recommendation. We have learned the hard way that it can no longer be so. Checks on adults working with children are expensive and time-consuming. The requirement may deter some good volunteers and infringe liberties. But as Scottish Secretary Michael Forsyth concludes, "the safety and protection of our children must come first".
What the people of Dunblane wanted from Lord Cullen's report was that it should make schools safer places. His proposals, accepted by the Government and strengthened on gun ownership, are welcome for a toughness that has responded both to Dunblane and wider public opinion.