That’s really the point. But you have it flipped around. You, as an experience referee, can come up with ways to handle things on the fly that are just as good as the mechanics in the book. Likely better because what you come up with will naturally more closely match your perspective, preferences, and style as well as the expectations of your table…and be better suited to the actual situation in your game in that moment.
Sure, but don't most games that have mechanics allow for this? Use your judgment and do what makes sense.
And what would be more concerning to me is what if expectations differ? What if my Mothership player declared a hiding spot that he thought was great, and I didn't?
Mechanics can be very handy to avoid decision making when that may not be the best way forward. I don't want to always decide what happens as the GM. I want the dice to have a say, too.
And, in the case of the Mothership stealth example... I didn't set a DC or TN or anything like that. I decided which of the existing mechanics we would use. I had to do so precisely because no specific mechanics exist for it.
Which would seem to go against Brennan's point... he wants mechanics for the things he doesn't want to spend time thinking about (combat), and not for things he wants to spend time thinking about (portrayal). His game doesn't have rules about portraying character, so they are in fact free to do what they like.
But my player wasn't free to just say "I hide" and be successful at it. Mechanics were needed.
As you say, the fairness comes from the fiction. I don’t see why that changes for edge cases or less obvious calls. If the outcome is not obvious from the fiction, make a call on the likelihood and roll.
But how is this different from when there are actual mechanics in place?
That’s the part I don’t get. As a player you’re always leaving it up to the referee anyway. They can declare it auto success or failure. They can decide to adjudicate the situation via conversation or mechanics. They can call for rolls and set the DC/TN, assign modifiers, give dis/advantage, etc. As a referee you always have to make these calls anyway. So all a system gets you is agreement on the dice to use and at best some guidance on setting DCs/TNs…but, ultimately, the decision is still yours.
No, not always. Different systems do different things. Some systems have no target numbers or difficulty classes or similar. There are static thresholds for success or failure. GMs can be limited in the amount of input they have over these elements through design of the rules.
I think it's pretty clear that Brennan and co in WBN and elsewhere have a system for character and social interactions and narrative arcs, it's just that the system is "extensive improv experience, a shared sense of story development and deep seated comfort with each other as performers." In other WBN material, Aabria and Erica talk a lot about their "writer brain" and "director brain" being routinely engaged alongside their decision making as players.
Aabria's character in particular in WBN is making painful, self-defeating decisions based on a flawed, imperialistic worldview without the aid of a mechanical system guiding her to make them. That's entirely down to a set of extra-system skills she's deploying as a performer, and it makes complete sense she and the other players would want to retain creative autonomy to make those decisions, instead of handing it over to a game system.
I think this touches on an important part. Their game is a bit different from what is typical for many... they are performing for an audience. They are all very aware of that, and are considering it with every decision they make.
But if that's not the case, would they be so willing to make such poor choices for their characters? Or would another group of players? This is where system can actually help. If play is meant to be about messy characters making poor decisions that complicate their lives... rather than being about a group of hyper competent specialists who have been conditioned to optimize every decision they make and to mitigate any and all risk possible... then why not have rules that actively promote that kind of play? Let's say something as simple as "Gain an XP when your character makes a poor decision that makes things harder for them or their friends".
Again, I think the nature of Brennan's game is somewhat unique in that sense... they are actively trying to make the game dramatic and tense through their choices. Because they are actively doing that, there's no "need" for mechanics that support it.... though I don't really think any such mechanics would have to be a problem. But for less performative minded groups who still want that style of play, mechanics can help guide them and achieve that goal.
If we want to simulate combat whether taking place in the framework of a story or not, we need a lot of props and algorithms to generate that other than conversation.
I mean, you could flip a coin.