A good example of some of the difficulties of this system would be TSKSR and Yoseikan Aiki-budo. At one time, it is my understanding that, the founder of Yoseikan Aikibudo (Mochizuki Minouru) had permission to teach his students TSKSR from the soke of TSKSR. At that time, he and his students were *doing* TSKSR. However, after that soke's death, the new soke (and senior teacher, not the same person) decided that they would not be continuing that arrangement. After that point in time, while nothing would have necessarily have changed in the way the Yoseikan folks trained, they would no longer be *doing* TSKSR. They might do the techniques of TSKSR (and I'm not getting into the debate about how well/authentically they do/did them) but they are not doing (nor are they part of) TSKSR.
Of course, Mochizuki Sensei was superlative in his sword training, but he never made a secret that he modified the TSKSR that he taught, based on things he learned from a police unit that trained for practicality in the sword and not to retain any historical accuracy. He made some big changes. We knew that the kata "came from" TSKSR, but we also knew that they were "not" TSKSR.