Bedrockgames
I post in the voice of Christopher Walken
I was reading that as geographical exploration. As I said in another recent post, it's not something I'm generally interested in, as either player or GM. A bit of it from time to time, in the form of unknown locations or super secret lairs or what have you, fine... but as a major goal of play? Not really my thing. Nor essential to a sandbox or player-driven play.
I am not super interested in this either and I don't see it as essential. I think you need a world. But that world could just be a Jianghu penned over a map of historical chine or your chosen setting. This is why I use hexes for distance in travel but wouldn't describe my campaigns as hex crawls.
I think what's causing the confusion here is the word established. Because in your first sentence, when you say established traits, I want to respond that if the traits are established... the principled nature of the guard, let's say... then there's no issue. But you mean established as in set by the GM prior to play regardless of whether the players know. To me, established means it's been made clear to all participants... it's been established in play.
I just mean the GM has this detail pinned down prior to it coming up
If you are not aware of given NPC's trait and then you make a roll and learn about it... how do you know if it was established by the GM beforehand or if he just established it on the spot?
You don't know for sure. That involves trust. The GM can show his work, and I sometimes do so that this is clear to players. But it is part of building trust I think. For me long as the GM is genuinely putting things down before hand, it is fine. And there may be cases where the GM has no choice but to come up with something after the players are already clearly going for the bribe (and as I said I would be much more cautious in those instances). But this is why I talk about pinning it down in that sandbox blog post I linked. It is about making sure if the players are about to make a blind choice of some kind, you have set it up as fairly as possible. I don't mind for example if I am snooping around a house looking for a suspect and there is a shed, and I go in, a murderer stabs me with a knife because I opened the door incautiously and he was genuinely there (even if the GM adlibbed the house and scene, if he noted that detail before I was making my decision, it feels more fair to me than if he made that decision because I opened the door incautiously and he wanted that kind of a moment). As long as I can look back in hindsight and say "well if I had been more cautious things might have turned out differently".
And yes, it does have to do with the roll... the roll indicates the chance of something... that there's a possibility, not one certain outcome. If a roll is made, it should feel like the roll mattered.
I understand, and I am not saying rolls are bad. But try to appreciate for some players there is tension between a roll deciding a social outcome, and their characters words and actions doing so. Some systems are better than others art bringing those together of course. But to me there is no replacement for freeform RP in this area of the game.
Immersion is something that's going to vary from person to person, so that's tough to say, but it seems like yet another priority separate of player agency.
Immersion is pretty connected in sandbox play to agency though. At least the way it tends to get used. I am not even someone who is super picky about it. But if you play with people who value immersion you will find this very quickly so it is something to be mindful of when managing a sandbox campaign