As a former school teacher and a first aid trainer I know that there huge differences. Not all school teachers are trained. One school I went to recently had nobody trained to meet their legal obligations.
I do support a charity called Hand on Heart which aims to get more defibrillators into schools and train up staff and pupils. www.handonheart.org/. 12-16 young people die every week in the UK from sudden cardiac arrest, 80% of victims will have no prior symptoms.