ah, well, something borrowed from elsewhere isn't phony, it's just borrowed. Personally, I believe in truth in advertising, so if something is borrowed, it ought to be acknowledged as such. But it may be just as good or even better than the original material from the system.
I guess maybe I'm fixating on you choice of words with "phony". That conjures up an image of some guy sitting in his basement, just making stuff up off the top of his head with no basis of knowledge on which to place it, and no ability to put it into use. That to me, is phony.
But a sifu with a good background of training and knowlege may create his own drills, or make his own modifications to forms, or even create his own forms to augment what he learned from his sifu. As long as this person is skilled and knowledgeable to begin with, before he makes these changes and additions, I don't see that as phony. I just see that as innovative. Maybe I would like his innovations, maybe not. But I don't think there is anything inherently wrong with this. Obviously not every schmoe should be trying to do this, but there are teachers who I think can do this and produce good results for his students, and it is probably more common that we may realize.
Remember: all of this stuff was just created by people, not by gods. None of it is sacred and unchangeable. Other people can and do come along later and make changes. Some are for the better, others for the worse, still others may have little or no effect. But it happens. At what point does it become in-authentic? At what point has it changed so much that it is truly a different method? I don't know, but I think every sifu has his own flavor of his art. And it is all authentic, altho it could be "wing chun with some changes I made", or "wing chun with a bak mei influence", or even "wing chun, but I also teach some bak mei forms", for example.
Again, I think this comes back to truth in advertising. The Shaolin reference is a big one. I know that some kenpo systems like to insert Shaolin into their name, but I believe it would be shaky at best if you tried to trace an actual lineage to shaolin. I think that's deceptive advertising. But parhaps their material came from somewhere, and in it's own way it's still authentic SOMETHING, just not shaolin. Whether it's poorly or skillfully done is another matter altogether. But in the end, it's all made up by people.