Pedantic
Legend
This gets at a fundamental question about GM authority in such games. I generally contend that GMs are inhabiting several roles, which have separate powers and separate functions. GM-as-Worldbuilder creates a setting and populates it with people, places and things. GM-as-Adjudicator resolves rules disputes and makes rulings (a role/need I think emerges primarily by having insufficient/incomplete rules). GM-as-Cast provides decision making power analogous to the players to all the non-player entities, with the caveat that the motivations thus portrayed likely vary significantly from those PCs possess.So to explain my thought a bit further, in 1978 a philosopher name Bernard Suits introduced the concept of the "lusory attitude" to game studies. As he put it -
There are virtues and flaws with that view (the latter hopefully won't matter here). Anyway, one thing one might say about players as players is that it suits them to adopt a lusory attitude (heh) and if they could change the rules on the fly that might put them in breach of Suits' observation. Traditionally, GM has been appointed to change rules, presumably not putting them in breach as they're not a player.
Some ideas about rules, in particular how and by whom they might be changed during play, seem to skirt either making GM a player, or voiding the lusory attitude. At the very least, some sort of balancing acts or constraints probably need to exist. So let's suppose that GM becomes a player and thus loses their making-rulings power... what then?
I view these as separate, distinct functions that happen to reside in the same person, and view the GMing role as having a professional responsibility to maintain each position's distinction. Discussions about declarative authority usually press the assumption this is impossible, and further that there is no ultimately value in striving for it; authority must be constrained by some other principle.
Rule 0 is a bad piece of design, and a worse piece of rhetoric. As a design point, it's primarily an abdication of the need to build a complete ruleset. As rhetoric, it encourages the GM to inhabit another role, that of GM-as-Designer, and to conflate that role with GM-as-Adjudicator, which is corrosive to a cohesive board state and player agency.