Not at all. If Sensei X trained in styles a,b, and c, and was creating katas in style a, then it would be prudent to consider what styles b & c might be contributing. In arts like kenpo where it is common to cannibalize things from other arts it helps to know something about the arts it is borrowing from. New katas are created to impart knowledge not included in the old katas, so if Sensei X is making a new kata for style a, it is probably to bring in new information from either style b or style c (or both!). Knowing that styles b & c went into this new kata, it is easier to isolate the newly introduced principles and may give the student more information to understand their art better. Now if you mean that Sensei X hid the fact that he studied styles b & c, and was thus not forthcoming in that regards, then sure that would make further exploration of the applications a lot harder!