When I was an active CMAS instructor (1978-1990), we were continuosly evaluated.Internal audits by the training companies for starters. Regional teams doing unannounced visits to classes by these certified instructors to make sure standards are being followed. Do we want to buy regulators from manufacturers that don’t do QC/QA? Why should training be any different?
At the end of each course, an external examiner was sent from another town, testing both students and instructors. Every minor deviance from standards was sacked and reported to the national technical commission.
Typically once per year, or even twice, we had to travel to Genoa or to Rome for a technical update meeting, typically involving also some tests in a pool.
This ensured strict adherence to standards and that all instructors were kept updated with the latest findings, skills, equipment.
It was a time of quick innovation, both technically and didactically.