Zooming in on this. What counts?
I recently was discussing things with a DM. One of their players was a bit brusque with a shopkeep who was pressing them about a personal issue. The Shopkeep was trying to be nice, but the PC took it as a complete stranger trying to dig into their personal life, and responded a bit harshly. So the DM had the Shopkeep burst into angry tears and throw them out of the shop. If that had been a hireling, would that be enough to break their loyalty?
What if the PCs decide to defy the Evil Overlord and his Evil Plans. Clearly such a figure would retaliate against them correct? And surely since they invited such attention, they have put their home in imminent danger, right?
And that is the problem. You may have a clear idea in your mind of about what constitutes these things. What behavior would cause a loss of loyality, what makes for putting their home in danger. But the players might not agree with your assessment, They in fact have no clue what you might decide counts. Oops, turns out that creepy statue they found is actually a cursed artifact, so now their Bastion is cursed with undeath and all their servants died. Too bad they had just grabbed it and didn't bother to research it, right?
And this is why I feel like it is fine to be a player's decision what goes on in their home turf. Because it prevents miscommunication and mismatched expectations.
That's like ... I don't even know we're to start.
If you play with the same group for longer than ... like 6 month or so, you know what goes and what not.
Like at my table that I DM we never had a problem with any of that kind.
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.