By this I mean, I have seen and know of schools who do a version of the taegueks. They have differences such as stances, where the Kiap is, and hell some even add extra and different moves. They do a modified Taeguek/Koryo/GuemGang/Taebeak/Pyongyong/Sipjin/JiTae... The instructors are not KKW certified nor do they certify or attempt to do it the KKW way...They SHOULD NOT CLAIM TO BE KKW.
Make any sense?
The problem with that is that the students don't usually know any better and may actually believe that what they are doing is the way it is supposed to be done. Perhaps the head instructor or the one that made the changes knew better, but over the generations, that got lost, and now you have these mutations who truly believe what they are doing is the correct way. I come up against that all the time, usually from people who argue I am wrong and don't know what I am talking about and yet refuse to provide any sort of factual basis for their strongly held, down to the middle of my bones, beliefs.
One example, long wide stances. Al Cole and I brought that topic up ten years ago and people were extremely angry that we would have the nerve to suggest that what they learned wasn't correct. We asked to to simply look at the Kukkiwon Textbook if they didn't believe us and they wouldn't even do that. Or if they did look, they felt that the Kukkiwon was wrong.
But I do believe that the internet is changing things and more people are doing google or youtube searches and finding out for themselves. Generally it is the younger generation who are not so set in their ways that are more open to change.