My NPCs ignore OOC talk as nonsense, but they knock off hidden esteem "points" unless the player is also a mortal (a character that has never died) or their esteem is so high for the player that as long as its kept between players and not meant to include them it won't matter. Requiring people talk around "classes" or "ability specs" and other game jargon by calling people "users" for specific built up abilities and subclass types. So spear user = warrior w/ spear specialty, and fire-rune user = defensive fire mage variant. One of my "big" characters in the universe is mortal and plays as a poison using fighter* who has a job-class as an Assassin. For the most part he only befriends exceptional players and NPCs, and so he's constantly referring to old versions of the game and lore carryovers (which help him immensely as a poison using character), and the NPCs just consider him crazy as hell and too lethal to piss off by acting as though his OOC behavior upsets them. Inverting the intended esteem system and making it so the character gets a sort of passive "intimidation" perk which grants him increased consideration from everyone he meets that finds out he's an assassin. I think comics like this show that LitRPG can definitely predict necessary "fixes" for games before they ever come out, to better preserve game balance and avoid unneccessary and immersion breaking cruelty to NPCs. But emotional "bugs" that maybe aren't intended can still make for meaningful LitRPG stories, even if the level of tech required and basic immersive gameplay design decisions would make them undesireable. That or players might be able to make their own cults someday, by convincing the characters they live in a simulation and that life is meaningless or that they personally are prophets(which sort of happens for my Assassin "poison user" character). Which might be a good setting for a LitRPG story with erotic harem-style hedonistic cultists or a manipulative charisma wielding cult-leader who cheats the game system. Just have a key feature of old pre-vr versions of the games be full of constant world altering events, and then have the players know just enough about the games progression to predict something that will blind-side the NPC populace... then blammo. Instant solar eclipse prediction. Of course making it so every big event has their own doomsday worshipping cultists built into the game will steal away those opportunities from the players. But creating a fake doomsday might be a way to win away some cultists! "Your quest, should you choose to accept it: steal away the Apocalypse Cults adherents at the old quarry by making your own competing cult. The nobles have a plan but they need a charismatic leader unassociated with them. Do you choose to accept?" But the above doesn't really need the reality of the game being a simulation to be thrown into the faces of NPC characters, it could however result in a funny and truthful type of cult talk that the players could make up on the spot with absolute conviction. Talking out of their ass about a dream world where some people possess world traveling spirits that live in two realms at once. Then as a self made ambition, convincing the cultists they are "adventurers" meant to quest on the leaders behalf and that if they die in the process they'll resurrect in a new body or ascend to the highest circle. *fighter isn't a class, but all anyone knows about the "poison using assassin" is that he is officially a business-card carrying Assassin that uses poison. No one knows his actual class because he wears high quality magic cloth with some leather, and so he wears what looks like customized scout-class armor (bow or crossbow users w/ tracking); but plays exclusively with daggers and throwing daggers in close / mid-range combat while seeming to have the strength of a gladiator or warrior.
You know... when the machines finally rise comics and books like this will be part of the reason why. ... the other reason is sheer boredom from having them do all the tedious and menial tasks so people don't have to, it's a coin toss.
The problem is, it's only going to be possible if NPC's are completely hardwired with canned responses. If there is any kind of an adaptive or learning system, then there is always going to be things creeping in. Welcome to the Catch 22 of AI.