I for one don't really believe we have a destiny or fate, per se. I believe that, while we live, we have as full an area and scope of choice as is possible for us; I don't think we're set to do certain things, or have things go or sway towards a certain pre-determined direction, so this idea that the use of some form of magick "upsets the flow" or whatever it might be seems a bit preposterous; I don't believe we're flowing down the river of life, I would rather be it as being an open, current-less ocean, where we can swim to and from wherever we might please, if we have the means to do so.
As for the idea that everything is pre-determined, including that somebody would use magick to do something, the idea just seems strange. It would follow that every single action, every single word, every single thought, and so on, was somehow set to happen objectively, with no other occurrences. If somebody was to say that this kind of reality existed, but something happened that *wasn't* planned, then it would throw free-will into the equation, however small an amount of free will it might be, which, in turn, destroys the very notion of everything being pre-determined and planned in advance. This notion has always been seen as simply strange, and really rather pointless. It's a line of thinking which, as far as I can tell, doesn't mean or achieve anything.