Not what I meant. Even if a move that slightly deviates from how it's taught in a style's method, it doesn't exactly mean you are no longer performing that art the moment you perform it.
If you super traditionalist, then sure, for that one moment, your doing boxing and then you switch back to kung fu the moment the punch is over. IMO, I can be doing any art, and as long as the move can fit within the style, you're still basically doing that art. Technically speaking, that move that isn't explicitly taught in your art could be labeled as a move from a different art, like the right cross. And technically speaking, it is. But let's say that in the exact scenario where you used it, it fit into the method or strategy of your style. It really only worked because your style and skill with it paved the way for that move to be executed. Does that mean you aren't doing your style? I don't think so.
Perhaps kung fu was a bad example. I don't know anything about kung fu. I really thought we were on the same page on that one though.