DCBC -- it is my understanding that a NAUI instructor could not teach a class identical to GUE Rec 1 -- at least from the standpoint of gear configuration. I'm not a NAUI instructor and don't have access to NAUI standards (and there are standards, are there not?) but I've been told that ALL students and instructors MUST have a snorkel attached to their mask at all times during an OW class. I know that GUE does NOT have such a requirement. As a PADI instructor I have the discretion as to WHERE the snorkel may be as long as it is in the possession of the diver. Perhaps a minor point, but just one that I happen to know (at least I think I know).
The Student must have a snorkel for the OW portion. There are no equipment configuration requirements, so the snorkel can be carried/stored anywhere where it's accessible. Although GUE does not have any requirement, carrying a snorkel is not prohibited, so nothing in the NAUI program would conflict with GUE Rec 1.
You seem to believe that NAUI's "flexibility" in teaching is a benefit -- and I agree that, in some cases, it is. OTOH, I also believe it may well be detrimental too for I, as someone getting a "NAUI Trained" student will really have no idea what that training may have been. At the very least, when I get a "PADI Trained" student I do have an idea as to what the training was.
With NAUI, every Student (regardless of Instructor) must meet the "Minimum Standards." So like PADI, the Standards (NAUI Minimum Standards) are universal and in-common with all Agency Divers. The difference that you are describing, is how much more knowledge and skill-sets the "NAUI Trained" student may possess. This is an unknown factor that will vary between NAUI Students (because of the individual NAUI Instructor Standards). One may be only trained to the minimum, while another to the academic training of a Divemaster.
Last point -- you seem to believe that the word "exceed" is equivalent to the word "deviate." Since many of us have written over and over again that we, as PADI instructors are encouraged, nay required, to "flesh out" the standards and as a regular matter of course, do so, you may well find that we "exceed" and/or "deviate" from those standards. We do not -- but you are welcome to your own fantasy on this point. Exceeding/expanding (expounding?) on the "standards" is what teaching is all about -- but such is not necessarily (!) deviating from those standards.
Exceeding requirements in my mind equates to a new knowledge base not covered in the Standards. For example, a requirement on the part of the Instructor to increase the minimum swimming ability of his students as a result of more demanding local diving environment. This is not "fleshing-out, or expounding" on the Standards. Rather it is a change to what is required for certification, in-consideration of where the newly certified Diver will dive in an unsupervised manner.
Another example would be an Instructor's ability to increase confidence through BB, station breathing, or blackout. Exercises that will increase the Diver's ability to deal with anxiety. NAUI considers additions to the program like this to fall under "academic freedom." A NAUI Instructor is not limited to what he teaches in what session, in what order, it's up to the Instructor in-consideration of the student and the individual Instructor's teaching approach.
My guess is that ALL agencies prohibit their instructors from "deviating" from standards -- otherwise, could there be such a thing as a "standard?" Granted, as a PADI instructor I may not withhold certification from a student as long as they meet (or exceed!) the standards as written, unlike, I guess, a NAUI instructor, but, honestly, as long as a student can meet (to MY satisfaction) the standards as written under the conditions in which we dive, I'm good with that.
Yes, a NAUI Instructor can withhold certification if either NAUI's or the Instructor's Standards are not met. The "Minimums" are established by NAUI. The certification requirements are established by the Instructor, but the minimums must be met.
Obviously the idea isn't to withhold certification, but to turn out competent divers in-which the Instructor would have no hesitation in certifying. My particular standard (as I have related before) is that the new Diver is competent to dive with any member of my family. To accomplish this, I include underwater rescue into the program. Simply because I wouldn't want anyone diving with one of my sons or wife that had no idea how to help them. This is a personal requirement. Every Diver I certify must satisfy it. PADI does not allow me this freedom.
So is a Diver more competent if he knowns underwater rescue? Some may think that it offers no benefit. The only person's opinion that matters in this case, is the certifying Instructor...