Alberto, I think Mark did snap at you a little bit, he's a grouchy old man sometimes . I will answer your question quickly before returning to the topic of the thread.
The reason we discuss these things at length here is that there is no other way for us to do it. If I want to get the opinions of people like Nathan or Mark who have a wide set of experiences different from my own, this forum is ideal. The people I train with tend to have similar outlooks to my own, and I can't tap into the wealth of knowledge that is out there in the rest of the world.
Most of us here do train intensively, but have got to the stage in trainng where we want to understand more than our small world, to quote Chuang-Tse "Men honour what lies within the sphere of their knowledge, but do not realise how dependant they are on what lies beyond it." We are looking beyond!
Anyway to the point at hand to me there is no problem with splitting away from the school if you truly feel you can improve on the training. As has been mentioned it's been done since the very beginnings of MAs. However there is a catch, I don't believe that the majority of westerners and some asians have high ideals when they split. Some do it to cash in on the business side, others for reasons of ego. Few understood enough about the arts to improve them.
Anything you are taught becomes your own, but to pass it on in a manner that detracts from your teacher is both an insult to him and a disservice to you. Arts should evolve and grow and this is achieved by re-examining the principles and improving them, not by taking the tricks that have been taught and re-teaching them, this is a weakness. Just as in the childs game of Chinese Whispers, the origin is lost and the result has little value.
Just look at some of the sport karate schools!
Regards
Neil
Neil Hawkins
"The one thing that must be learnt but
cannot be taught is understanding"