Indeed, it doesn't. It would merely be for edification of the participants.
Player is aware of the relevant details. The player knows what situation the GM describes (e.g. swarming spiders appearing) and they know how their character feels about spiders. No world editing is happening.
You literally quoted the words "
Because the player is incapable of knowing details that may or may not be present that they are unaware of they must take that step or [of making a case]" in the same post that you declared that the player who is told they are affected by something with details they are not yet aware of knows everything "relevant" to deciding if their reason for choosing to nosell the apparent affect is justified. The spider example is also one you have wildly misunderstood, it was originally made back in
676 by
@CreamCloud0 as a no broader context needed example of a player trivially making a case for why they should be unaffected by what seems to be the source and it was implied the reasoning was just as trivially given a nod of agreement.
Since you seem to think that the player is incapable of not knowing relevant details to the point that such a simple process of trust but verify though I'll expand on it to show a hypothetical unknown that the player could be unaware of. If those spiders that seem to be the frightening thing were simply fleeing the same burrowed sleeping dragon dormant god ancient evil or whatever that is starting to wake up then it's entirely possible that the gm chose the swarm of spiders as a hook to past declarations the player had made cases for over the weeks and months of play with the expectation that the Australian drow pc player or another player would bring it up giving such a devout follower of llolth a warning to the growing danger. By making the original case they could be told that it's not the spiders that are causing it and the player could even be made aware of how their devotion had led to lolth blessing them with that tiniest of warnings they something had changed.
I am not shifting it. That is where its place is. You're trying to shift it under GM approval in your railroady desire to control the characters.
Wow... You can't even grant enough acceptance to the idea that the player might not know all of the details for why a thing is affecting them in order to distinguish the difference between making a case for why something should not affect their PC and unilaterally deciding to "narrate" that it simply doesn't.
I am not interested playing in game where I need to debate with the GM in every turn whether I get to decide the personality of my own character.
We aren't talking about a game you would play in, we are talking about the game as a whole and you have already declared that making your expectations known by flying your rwd flag loud and proud during session zero was not something you would do as a player.
Nobody invited anyone to play a game.
It doesn't really matter if you want to play in a game where a player's PC is constrained by the game world's reality in ways that may be more involved than what the player knows about it so far
L
Seriously, why you feel the need to do this? As a GM you already control the whole world. All the NPCs and creatures, everything the PCs hear and see. Is that not enough? Can you not let the players play their characters in peace?
That is apparently not as true as you are of claiming. By your own position that bold bit is subject to the whims of a player to decide for themselves about the world even if their PC is currently being affected by something they do not or could not
yet see without further action investigation time or the like.
"Tell your story" as marketing for a game where a shared tapestry of story evolves over time through play where each participant is working in parallel with their own unique contributions has always been incredibly misleading and toxic in ways that encourage the worst & most disruptive of Mary Sue/Gary Stu impulses to be wielded against the GM's efforts to actually gm the game & it's world where that shared story evolves