But I also never had a player demanding that there are things in the game that can't be affected by anything.
The closest maybe is ... a PC had a brother, that they now met and after speaking with the players about hownI can use him the rule was not to kill him, everything else was fine.
Another PC had several half-siblings running around he didn't know about, the player of that PC first had the Idea to give me the (already created) siblings (it was a preexisting character) but then decided against that and let me create new ones, because the player thought that it would be very hard to do them correct (and they were part of the Plot).
Like ... when we put it in the game world it can be affected by the game world. I always played and DMed like that and never met a player (at my tables) who wanted it otherwise.
And there never was a problem in that regards at my table because my players trust me. And when I'm unsure about something I ask them and when I see them doing something that could have consequences they as players are maybe not aware of, I usually warn them.
Like last session they looted the pirate base they just conquered and found a lot of magic items the pirates weren't using to fight them (hint 1). Of course the wizard does, what a wizard does and spams identify and as a DM I reminded the players, that Identify doesn't tell you, if an Item is cursed or not (hint 2).
So, now, if they just put on the Items anyway, it is on them if they get cursed.
So, now, if we had an Off-Limits Rule for a Bastion I would usually warn the players in similar fashion, that the action they are taking could make the Bastion vulnerable.
But in general in session zero I would tell the players that I don't play with Offlimit Rules if WotC put some in.