This was common in all Eastern Bloc countries. In Poland under Russian occupation UB/SB https://en.wikipedia.org/wiki/Służba_Bezpieczeństwa https://en.wikipedia

This was common in all Eastern Bloc countries. In Poland under Russian occupation UB/SB https://en.wikipedia.org/wiki/Służba_Bezpieczeństwa https://en.wikipedia.org/wiki/Służba_Bezpieczeństwa "secret police responsible for internal and external intelligence and counterintelligence to fight underground movements and the influence of the Catholic Church" would send its agents to schools to befriend children and try to get them to rat on the parents.