This question is specifically about the reaction of people in a class-hierarchical society, one that has never seriously considered egalitarianism, to a modern person with modern ideals. I imagine there's a good treatment of this somewhere, but my searches haven't shown anything.
I'm imagining an articulate modern guy in clean but casual clothes, like jeans and a collared shirt, something like that, who finds himself in 18th century England, or any place and time where class stratification is much more pronounced than it is in 21st century America.
How do the lower classes treat him? How do the upper classes treat him? He really doesn't fit squarely in either group, but would the upper classes look down on him even after they've exchanged a few words with him?
Of course it would be different in different societies. How would pre-Revolution French aristocracy treat him? An earlier India that has never had its caste system challenged or tampered with by imperialist influences (assuming it ever has)?
I leave the treatment of a woman's experience to another discussion, it likely being very different.
Maybe is this just too broad a question?