Depends where you are talking about. China certainly had formal travelling papers, and god help you if you were a peasant without them if you caught the attention of the powerful. While it's true that photo ID requires photography, recall also that forgeing hand writing and signatures is not a simple task when your 'mark' has an experienced eye and knows the writing of the person you're trying to forge. The governing classes, even in a place as massive as China, tend to be fairly small and to know each other. In fact the Chinese beauracracy would rotate officers throughout the empire, both to ensure they knew each other and to prevent them from building local power bases. Plus modes of speaking and writing vary by social class, and it's very hard to fake your way up or down. Frex in "The Hidden fortress" when the princess traveling in disguise had to pretend to be mute, as there was no way she could fake speaking like a peasant.
Japan and various parts of Europe in calmer times had similar levels of "lockdown" at certain times, with papers needed to go anywhere and so on. They functioned quite powerfully in times without war, significant rebellions, and so on, where a largely unified bureaucratic empire was able to impose control.
However, that is not at all the default/normal D&D situation. In virtually all D&D settings, the world is in chaos or semi-chaos, with roaming bands of humanoids, dragons, monsters of all descriptions and so on meaning that there is
absolutely no way that the place in that level of lockdown. In the FR, for example, there is no unification across most areas, no real bureaucracy, just dozen and dozens of city-states (or smaller units, even!), or partially-broken countries, and there is absolutely no way they are running a setup like this. There may be individual nations which manage a degree of lockdown, but even they are pretty pathetic compared to the peak of Chinese bureaucracy.
I think it depends on where the table is located.
Here in the states a lot of people seem to have a very hard time indeed grasping the concept of showing respect and deference when speaking to others. See the "Mouthing off to the BBEG" thread.
"Mouthing off at the BBEG" has nothing to do with historicism or understanding history. It has everything to do with drama and so on. If you are running a game where the PCs have to bow and scrape before the BBEG who they know is the BBEG, that's a pretty specialist game, and one that eschews what is dramatically appropriate and exciting for a certain kind of tension. You absolutely need player-buy-in for that, and you need to make it clear beforehand that it's "that sort of game". It really has nothing to do with whether people understand real history.
Further, if you expand "not understanding how respect and deference work", then, both in my personal experience and reading about/hearing about other people's games, and indeed from this thread, it seems to me that
Dungeon Masters are actually the
prime offenders here (if we exclude hormonal teenage boys), frequently creating situations where NPCs are abusive and disrespectful towards PCs who are vastly more powerful than them on every possible level, and then expecting the PCs to "just take it", because the DM has decided that they must, or where they expect PCs to behave in a certain manner, but totally fail to clue them in to it, or give them a reason to behave that way. Back in 2E I saw a lot of pre-written TSR and Dungeon adventures which seemed to involve some NPC being horribly rude and disrespectful towards a powerful (i.e. 7th level+) group of adventurers who he wanted to do something for him, too, when he obviously was only hiring them because he didn't have the resources to deal with the issue in a more direct manner. That's pretty silly stuff. Anyway, short of it is that if you expect the PCs to be respectful and so on, you need to have NPCs treat them with appropriate levels of respect, which are actually rather
higher than D&D typically skews. Obviously things can go downhill, but if you start out with NPCs sneering at the PCs (as a lot of DMs have, ime), trying to demean them, trick them, and so on, you're setting up a more disrespectful, "Wild West"-ish world, rather than a more medieval one. Insults, sneering, and NPCs looking down on the PCs should be a cause for comment in such a setting, not the norm.
There are obviously situations where an NPC will regard himself as so high and mighty that he would sneer to deal with such "mercenaries" (though this breaks down when you consider many PCs are going to men of the cloth, bards/minstrels, and others who are, by societal tradition, typically treated with respect), but in that case he should send an underling of appropriate rank who can deal with the PCs respectfully.
Given the dearth of interest in history, historical fiction, and historical wargaming among the under-40 crowd, I suspect it's a generational thing. Fantasy has largely taken the place of historical knights and sagas in the popular imagination. And precious little fantasy these days gives more than a passing nod to the gritty reality of medieval society. George RR Martin is the big exception, but part of his popularity comes from the fact a gritty medieval world is actually a refreshing change from most other mainstream fantasy over the last 20 years.
Hmmmm. I see absolutely no evidence that this is an "under-40" thing, except with historical wargaming. There is an issue were over-40s are always more interested in history than younger people, as a whole, but that's no more or less true now than in 1980, AFAICT.
I'm 36, and it's easy for me to see that there is VASTLY more historical fiction and quasi-historical fantasy on TV now than there was 15 or 25 years ago, yet if it was a 40+ thing, that wouldn't be true, because you're on the edge of the main group for TV at 40+. Actual history and archaeology shows are a huge part of the British TV schedule (I can't comment on America there). Movie-wise, there are just as many historical movies now as there were two decades ago, and indeed the situation is certainly improved from the '90s, not degraded.
Looking at books, fantasy and historical fiction continue to do very well. I don't see any evidence of a decline there.
As noted though, historical wargaming? Yeah that's on the way out, for a few reasons - it was on the way about by the 1990s, though, if not the 1980s. Financial cost, space required, time-cost-vs-reward, plus the availability of computer games which fill many of the same needs (whether the Total War series or Mount & Blade or Crusader Kings II or whatever) mean it's just not viable. Particularly in the UK, where, to do
proper miniature painting and games, you basically need an entire room devoted to it (and not a tiny one), something few people have to spare in this era. None of that is to do with less interest in history.
As for your " a gritty medieval world is actually a refreshing change from most other mainstream fantasy over the last 20 years.", sorry, no that appears to be completely wrong. You mean, perhaps, the 20 years before 1995? Which was when GoT came out. Or the 20 years before 2000, perhaps? By 2000, the fantasy market had changed vastly. Tolkien-esque and quasi-Arthurian/Celtic settings which were non-gritty were long on the way out by then. Since 2000, we've seen more and more gritty, grim, scary fantasy, to the point where it's certainly the core of the non-merchandised fantasy market, and even the lightest stuff is pretty gritty compared to, say, Terry Brooks or Tad Williams. In fact, for the last 5+ years, the standard whine from people who actually read a lot of fantasy is "It's all so dark!". So yeah, no, definitely NOT "the last 20 years". Perhaps "fantasy from people's childhoods" or "fantasy from before 15 years ago".
I mean, GoT is 1995, Assassin's Apprentice is 1995, Gardens of the Moon is 1999 (Malazan), Perdido Street Station is 2000, Prince of Nothing is 2004, The First Law trilogy is 2006, KJ Parker has been writing super-grim fantasy since 1998, and so on. GoT was the vanguard of a grim and gritty revival that continues to this day. It was published 19 years ago.
Judging by the most popular D&D settings and supplements out there, few players have any interest in the game world being anything more than superficially medieval - basically, no steam-powered or later technology. Socially, most published fantasy worlds are a cross between late 19th century American homesteaders and early 21st century suburban Seattle.
I agree, but this absolutely no different now to 1990, say. When 2E launched, it was with two settings - the FR, via FRA, and Taladas. Taladas was vastly more true-to-history in a way completely relevant to this discussion than, well, any D&D setting since and arguably before (certainly vastly moreso than Greyhawk or Mystara). Which of those flopped, and which did great? We all know the answer. So this is nothing new.