Say, if I were an instructor maybe I wouldn’t object too much to get an annual physical to proudly maintain my cert. In your survey you kinda lumped instructors and ’regular’ divers together. Instructors are somewhat similar to commercial divers in that they’re also making big bucks off diving (okay, I’m obviously kiddin’ here). Point is, a higher level of responsibility might just warrant a higher level of physical check-ups. A commercial company doesn’t want their divers to screw up and cost them big bucks, that’s why they check them annually. You’d think that a diver training organization would also require their instructors to get an annual check-up so as to not possibly cost them embarrassment or even lives of students in the worst case scenario. Yet, they do not have such a requirement, I guess there are other factors at play here, ask PADI.