Underwriters in my business require the policyholders do a minimum 2-day refresher course/year, and the policyholders willingly pay for it. And I see the difference in attitude with many of the screeners I meet like to make up rules as they see fit rather than think (or even know).

Did those screeners pass their refresher course in the previous 12 months, very likely. But what exactly was taught can be easily measured on how they interact with passengers 2 months later.