Aviation authorities worlwide should, and should have long ago, jumped on these "pimp my ride" scheming bar-stewards.
Why would they? They are policing standards and not ethics. A regulator is only interested in ensuring that a crew member has been trained to the required standard and is safe and competent to operate. How they achieve that is not within their mandate. Until there is a firm link between such schemes and safety, then the CAA (or whoever) have little reason to intervene. It is potentially dangerous to put all 'pay to fly' schemes into the 'unsafe' category, since the more reputable training organisations and operators, do indeed set the bar high.
The finger should not be pointed at the CAA, for now at least. It is the unions, representative bodies and those in airlines that adopt such schemes, that are to blame. The time for lobbying was years ago and not now.