SeanQ:
In a hypothetical situation, image GUE defined one method, and only method as DIR; meanwhile, another organization, such as NAUI for example, may consider two methods as perfectly acceptable as DIR. In other words, GUE divers would only accept one way as DIR while NAUI divers could accept either method as DIR.
Now imagine a group of both GUE and NAUI DIR divers intermingling(!) together on a dive trip. Let's use deco planning as an example for the DIR accepted method(s). Divers from both organization consider their own deco as DIR, however, as a group they would not be DIR because they have different deco schedules and are not standardized.
Am I on the right track or am I way off base?
Since no one is still reading this I will go ahead and chime in. While I can be a real %$@!* about the very technical details of DIR, I don't care about the number of cards you have in your wallet or what agency they are from. I personally do not have a single GUE card. Everyone getting up in a twist about is this agency's DIR the one or not is missing the point about what DIR is to an extent.
I am not a huge fan of how GUE is run on an administrative level. However, most aspects of the dive industry are not run very well IMHO. My expecations on this are probably a bit high though since most of the companies I deal with daily have a few more zeroes in their revenue lines than the entire dive industry combined.
Having said that, GUE's philosphy and how they enforce their standards makes the other training agencies look foolish. Because of this style, GUE will, hopefully, always remain very small. That is why a lot of people ascribe so much faith in some one certified by GUE. Personally, I can do the same thing with a five minute casual conversation and a glance at their gear configuration. However, knowing someone is GUE trained can be very helpful to those newer to the sport. A NAUI card will never have this appeal. If you are in the know about the industry, knowing someone has an AG card will cover the same base. But, this is a difference.
AG and I am sure some other non-GUE instructors out there teach very good classes and give students a strong foundation to grow on. AG, and I suspect the others too, does tend to slightly diverge from the very fine details of what DIR is. In some cases, these may be improvements. In others, they aren't. In some environments, it does not seem like, and isn't, a big deal. (Still does matter, just very, very little.) But, as the scope of the dive and the severity of the environment goes up, these very minor details start to matter more. Case in point, I had a stainless clip jam on a HP hose and simply used a double ender to clip off for a recreational dive in Caymans last week. Would I do that on a cave exploration dive with a bunch of stages hanging off the left hip ring. No, I would fix it before the dive.
There is a true every single detail DIR and there is what most people do which is gets close enough for the dives they are doing. Either because they don't know the fine points or mistakenly think their way is better or just don't want to bother. GUE properly empasises the every single detail approach. No other agency does and I doubt they ever will. Does that matter for picking your buddy for an open water dive that has the core DIR principles down - No. Will it affect your development if you are one of the very few people whose diving progresses to the sharp end of this sport and you don't covert to the little details - yes.
Diving has more factions than a PLO meeting. This problem is unfortunately here to stay. There are a lot of people in the indsutry that have an agenda against DIR, and GUE in particular. GUE will always face political garbage like this. Most of this stems from how little money there is in the dive industry pie chart and everyone wanting the biggest piece they can grab.
DIR as a concept has no agenda other than to develop the safest way of doing dives. This concept has enormous utility in all diving but particularly on the extreme spectrum. Since most divers aren't out there this far, many have a hard time realizing the full value of all the fine details of DIR. GUE attempts to convey this as an agency. But, there will never be more than a limited number of people that aspire to that. If other agencies at least improve their curriculum some, that is a positive. But, the other agencies aren't equipped to deliver what the DIR concept strives to be.
(sorry we didn't get to dive together in C.I. I was busy chasing my triox cert, which I just heard I got. Yay.) So if I choose to go the NAUI route, stick with Joe as an instructor, will other buddies shun me? I hope not. If I decide to stick with GUE will Joe be pissed? Hope not. I do know people who will be going their separate ways, and I think it's a shame because this whole deal is based on other people's differences. 
