Jim, I have to say you are very entertaining to read. Of course I always picture Will Smith saying something to you like he said to the military boy in Men In Black (...best of the best of the best....!).
Do you have your new OW divers sign a statement to the effect that their training has only prepared them for conditions similar to where and what they were trained in?
So the quarry trained diver plans their first dive at a tropical ocean reef shore dive site, with tides and waves and current and surge and coral and fish and they are in different gear and they don't know how much weight they need and they heard about the turtle cleaning station but they don't know where it is, but the vis is better than they have ever dived in. So if they follow your training, do they just do the dive on their own?
Did you even read my post? I'm not talking about those who WANT a DM if conditions are different or to see a particular place or thing. I'm talking about those who NEED it because they did not learn to weight themselves properly, control their buoyancy, navigate a simple out and back course, or aid their buddy if they got in trouble. But if they are properly trained and have the necessary info on site, conditions, location of the cleaning station and, as my students do, know how to determine their own weighting requirements then yes there is no reason they should not be able to do the dive on their own. Why would a certified OW diver not know how much weight they need or how to determine it? That translates to inferior training.
Why would they not know about tides, surf, current ,waves and the effects they have on a diver and how they can affect conditions? We have one lecture covering that.
They should also have the judgment to determine if the dive is beyond their abilities. This is all basic stuff. And why should any gear be unfamiliar. I have my students, over the length of a course, in basic bc's with weight belt, integrated bc, back inflate, and maybe a BPW. We do weight checks in each set up. By introducing buoyancy control as the first skill on scuba and then giving them time to practice it all that changes when they change gear is the way the bubble moves and the amount of air needed. Not a big deal. Of course I expect them to be doing basic skills hovering horizontal in midwater by the end of scuba pool session 2. Usually they are doing it by the end of session one on scuba.
This is the difference when it comes to a 32-40 hour skills and education based course from others. Technically an SEI OW diver is certified to 100 feet. We do not recommend it of course but they do have the knowledge(deco procedures, rescue skills, and task loading drills) and skill sets to do this. What they lack and it is made clear that they do is the experience.
I would have full confidence in two of my OW students being able to do a dive in new place, with new but equal or better conditions, and not require the services of a guide or DM and would trust them to take my son along who is only OW as well with them. They would have the judgment, knowledge, and skills to evaluate the site, decide it was in their range of comfort and abilities, plan the dive, execute it, and return safely. They would also be able to say that no it was beyond their comfort level and call the dive.
I would not expect my 62 yr old divers to do the same site as my 20 or 30 yr olds if it involved a long trek over difficult terrain. Or if the current was stronger than they would like to contend with. But he point is that THEY and not some guide or DM who does not know them would decide what is their best plan and dive that plan.