It's mostly just a social politeness/cultural thing, especially since most people wouldn't really want to engage in a long/complicated conversation with someone

It's mostly just a social politeness/cultural thing, especially since most people wouldn't really want to engage in a long/complicated conversation with someone who probably isn't that great or fluent in Chinese Even if a tourist gets into a loud shouting match about Chinese politics in a public space, the faux pas would be more social embarrassment than actual fear of state-sponsored retribution