Primary pupils as young as nine were given a harsh warning at a fire safety talk this week: "Start a fire and you will be locked up."
Graphic images of gutted classrooms were shown to youngsters at a conference aimed at cutting soaring incidents of school fires in Neath Port Talbot and Swansea.
They were also shown press reports of young firebugs sent to prison for igniting them. But conference organiser, Mid and West Wales fire and rescue service, also encouraged primary pupils to turn detective to help prevent school fires - particularly during the school holidays. And fire-fighters urged puffing parents to stub out cigarettes at the school gate to set a good example.
In the first Welsh scheme of its kind, teams of eight pupils have been asked to gather fire-prevention evidence around their school playground, including evidence of old fires, over-filled bins, binge-drinking and smoking.
Wearing fluorescent yellow arm bands, school "safety squads" have been told to dial 999 if they find evidence of an old fire. It is hoped their regular inspections and reporting of break-ins may uncover intruders responsible for starting blazes.
However, dog ends, the result of parents smoking at the school gate, could set back evidence-taking, according to safety squad officer Nick Dodd.
He told teachers and pupils: "Arsonists don't take fuel to start school fires - they often find it within the school.
"If your school is a mess then it will be treated as such. Over-filled bins should be tackled and reported, graffiti should be cleaned up."
Janice Gregory, chair of the Assembly's social justice committee, officially opened the conference at the Princess Royal Theatre in Port Talbot on Monday. The focus was on Year 5 pupils, who were treated to mid-morning coffee, lunch, and a resource pack complete with badges, armbands, clipboards and pens.
A spokesperson from Gors primary in Swansea, one of the participating schools, said: "Fires can wreck communities. Everyone has to be more aware of trespassers and report anything suspicious."
The most recent fire in the city gutted 1,013-pupil Penyrheol comprehensive in Gorseinon, with damage running into a six- figure sum. Pupils only recently returned to the school from makeshift classrooms after the inferno in March. Leading firefighters later admitted the school had been on a list of 20 Swansea schools at high risk of arson.