.. PADI has no rules governing such things, and it has no authority to make such rules.
They could pretty easily make it a condition of membership, to both individual pro and/or IRRA (resort) members.
It'd be a simple line of print within the membership contract. It could be implemented globally and universally across the agency at the time of membership renewal.
PADI has absolute authority to impose any
membership clauses that they deem beneficial. Providing such clauses do not breach or contradict other laws or regulations across a broad geographical reach.
Such membership stipulations could cover not only depth based restrictions for non-course diving activities, but also other environments (
like wreck or cave penetration) or even specialist equipment, for which the customer isn't qualified.
It could save dozens of lives per year.
It'd also make resort/centre memberships (i.e. "5-Star Dive Resort") ... and divemaster memberships... count for something outside of the strict parameters of training courses. Because at the moment they count for
nothing.
It's sad to know that many customers might choose a centre to support their fun diving activities in the grossly mistaken belief that these agency "5*" etc statuses actually mean something tangible in respect to that companies' operating standards and the diligent application of duty-of-care.
PADI might lose a tiny number of centres to other agencies as a result, but it wouldn't be drastic. Given that the vast majority of centres globally
are PADI members and all would have the same rules to abide by.
I suspect their chief barrier to doing this would be a fear of litigation... that by imposing safety standards on fun diving operations run by it's members the organisation they form a connection with such activities that, until now, they've been able (and glad) to keep their distance from.
We can speculate where the
true balance lies between safeguarding diver safety and litigation avoidance / financial safeguards.