In the Storyteller System (Classic World of Darkness, Orpheus, Trinity, Exalted, etc.) and Storytelling System (New World of Darkness) White Wolf included the Golden Rule (their version of Rule Zero which expressly defines ST/GM Fiat.
So... when questions come up that are not expressly RAW but there is a RAW GM Fiat rule which one takes precedence?
Related question: (?) How to answer a RAW question when the RAW are silent?
I made a valiant (my opinion) attempt at answering a question that consisted of a RAW portion and one that, arguably(?), needs GM fiat for full clarification.
Granted, there are edition issues which I did not know/account for but the root question remains.