Context Orientation is a term one generally hears in Anthropology, and Business Sociology. One way to distinguish environments, cultures, as well as business and social situations is "high and low context". I mention this because I think it is the high context situations where people on the Autistic spectrum have a much harder time learning the ropes. Low-Context cultures, which tend to predominate in the Western world (especially in industrialized regions), tend to be more transparent. Rules tend to be more written and social expectations tend to be "above the radar". Low Context cultures tend to be in areas where there is a homogeneous population, greater familiarity, or even oppressive situations where people don't want to be easily read by outsiders. These environments tend to have more nuance, unwritten rules, "secret handshakes"... No culture or environment is perfectly one way or another, but knowing the context orientation can tell us how literally or "at face value" we should take the rules. On the other hand many unwritten rules remain unspoken for a reason whether fair or fowl. One of the most universal unwritten rules is not to discuss unwritten rules in polite conversation. Doing so will easily result in defensiveness, a flippant denial that such unwritten rules exist, and being accused of ...heaven forbid...stereotyping. (Of course no one could stand stereotypes and generalizations unless they're ones they agree with, and they're coming out of their own mouth. ;) Many places we go have written dress codes or age limits which are strictly enforced. This is low context and generally not a huge problem for people with ASD to deal with. Other places may have an unspoken dress code, age limit, or gender expectations, this is high context.
We are still expected to follow rules even if their unwritten. These rules change over time and may even include not taking the written rules too literally. (an example in some traffic situations on highways not being willing to go one mile over the speed limit can be downright dangerous and stopping at a stop sign when the roads are a sheet of ice and no one else is around can lead us through someones garage door.) A more social example is that if a man goes into a hard core biker bar in the middle of nowhere. He comes in with designer clothes and orders an apple martini. There might be no written rule against it but it might not go over very well. Not to "stereotype" I'm sure there are bikers that can appreciate an urban drink but still, were expected to know the ropes and being naive is no excuse. Likewise were supposed to know not to go into some upscale stores on 5th Avenue in New York dressed in jogging clothes and ask how much their cheapest shirts cost. Some unwritten rules are obvious, while some are difficult to teach in words and depends on our intuition and the context of the situation.
Luckily today we have the relative safety and privacy of the Internet to get some of this information. We can go to business etiquette sites and learn unwritten rules for different countries without being scolded for generalizing. We can even look up slang words and understand what they mean.
Another thing that could happen when we inquire about the unwritten rules is the kindly patronizing "Why should you care what everyone else thinks of you..." Of course we shouldn't but to a point everyone does. We need to care what a prospective employer thinks of us and know enough to be on time and well dressed for an interview. Many people on the Autistic spectrum are already individualistic and could care less about "coolness" or the Zeitgeist". Breaking some unwritten rules however come with unwritten, below the radar punishments and consequences. Another unspoken rule is not to question them or else you may get a flippant "I don't know but that's just the way it is". A more extreme example the US Constitution has no prohibitions against eating cats (though its possible some smaller jurisdictions do). Either way even if it was allowed it is something that just isn't done... thankfully.
While many unwritten rules have an understandable purpose, many aren't even fair and should be questioned (even it it carries consequences). An example would be the many taboos people in many places have regarding race, gender, or social class. Questioning such rules may expose their irrationality and absurdity.
Here's a good website that explains context orientation better than I can: