J.R.:Yea... I know what you're saying... but the instructor is acting *in agency* for the agency... ie., they must follow agency minimums, standards and practices. The instructors don't make the rules... they follow them. It's the agencies responsibility to oversee the operations of their members and to ensure standards are being met...
... now, whether or not they're actually doing this... that's a whole nuther' kettle of squid... but I think you'll find that *legally* the instructor is simply attesting to the certifying agency that the agency's requirements for training have been met... the agency, acting on the word of the instructor... then certifies the diver.
An instructor may be acting as agent for the agency, but plays the closer and by far, the more important role in the certifying new divers. My point is that an agency's standards are the same to all the instuctors who teach for that agency, however not all instructors for that particular agency will have necessarily the same interpretation of its standards and aherence to those standards, which then can result in what we see as divers with substandard training.