I've excerpted this one bit because I think this is absolutely emblematic of the disconnect between posters, here.
If you said this about a Blades in the Dark game, it would not make a bit of sense. Like, totally, absolutely, just wouldn't make sense. It's so far outside the concept space that the idea that player input could stall the game or nothing interesting happen would be contemplating a complete failure of the game. It would be like saying that having the GM present a plot hook in D&D would result in no one knowing what to do and the whole game just stopping entirely (because the GM presented a plot hook). That's the kind of doesn't make sense I'm talking about. This statement just stopped me hard in my tracks.
So, why is that? Well, because it's true and absolutely wrong at the same time, and the way you read it is going to be very much how you approach the play of the game. If you're very much centered in the received wisdom of RPGs as handed down through D&D, then the statement makes sense. If the players are declaring actions that aren't progressing what the GM has prepared, or that are prompting the GM to make up stuff the GM doesn't care about, then absolutely play will stall. And, equally absolutely, the GM should prod the game to move it a bit and hopefully get to play that isn't stalled (well, I think
@Lanefan would say the GM shouldn't prod it and just let the players stall out if that's what they choose to do). And, this makes perfect sense. Like, 100% agree that from this framework (which is, by far, the most common one in RPGs and perfectly cromulent) this statement makes sense!
But, from a different framework, it's nonsense. And it's nonsense because you can play RPGs where the player's declarations are what's at stake - they literally cannot stall the game because that's what the game is about. You can't have a game otherwise. And, if you're not familiar with this approach, if you have no experience with it, then this is making no sense to you -- you're imagining a lot of play exactly like you know and are instead imagining the GM doing things that don't make a lot of sense and seem frankly horrible to you if they happen to make this thing I just said make sense. It's cool, I was there once, too. But, here's the thing -- it does work, and it does make for awesome games (not better games, just awesome, like the other way can have awesome games, too). And, in that sense, the statement I quoted is absolutely nonsensical.
So, if you're a person that cannot imagine a game that operates in a way that the quoted sentence makes no sense without going to horrible examples of play, then this is the reason for the disconnect in this thread. I 100% understand and recognize the play being defended in this thread (although why the need to defend it exists I am a tad baffled by). I was taught to play that way and played that way for decades. There's nothing to "living sandboxes" that is surprising or unique to me -- if anything, this exactly describes the first AD&D game I joined, and the 2e and 3e games I ran. Why? Because that's how I was taught to play. But, I've since spread out, and play games that don't follow this paradigm, that are different, and that do very different things. And so, the statement I quoted is one of those things that makes total sense to me but also is nonsense. Just depends on which way I approach it.
An odd aside:
Imagine a person that has only ever known and eaten lima beans. They love lima beans, and they've prepared them in a number of ways and with different spices and seasonings. This person thinks they have the culinary world on lockdown -- they are the master of the lima bean! And then they meet someone that's talking about this weird food called steak. So they ask questions. How do you prepare steak? They hear you can grill it or roast it, even eat it raw, there are all kinds of ways to make steak. And they think, that is like lima beans, I can make lima beans in all of those ways. Steak is not different from lima beans. Then they ask, how can you season steak? And they hear about salt, and pepper, and sauces, and they think, lima beans can be eaten with these. Some, maybe, do not sound appetizing, but indeed, there cannot actually be any difference between steak and lima beans! And so, they declare they know all the things there is to know about steak, and that they need not sample this steak, because there's not any real difference between steak and lima beans. They are, after all, the master of lima beans!
I dislike mechanics like Covering Fire whose utility directly depends on the GM's choices for how to mechanically model the fiction precisely for the reasons you list--it makes it much harder for the PCs to understand how their abilities can be applied if given only an IC description.
