I've lived in South Korea for over 10 years, though 9 months of that was in China. I did have open discussions with students outside of class in China about the country.
In China one of the students I became friends with (he was one of the top students in the class) told me he wanted to join the "party" and get a job. I told him frankly he'd probably be better off getting out with the corruption going on. He agreed that the corruption in China was bad. His girlfriend was in the same class and I said that I hoped she'd talk him out of it. I was there when Kim Jong Ill died and made an announcement in my classes that day.
Here in Korea politics is not something people want to talk about. I am married to a Korean so I have family here. It makes them squirm a little bit when I talk politics. During the last presidential election I was not happy as I was pretty sure the conservative candidate was going to win. The family sat down for Chuseok (Korean Thanksgiving) I was pretty vocal about my dislike of the person and state that she was going to be elected (I was right). My FIL said he was going to vote for that person and I begged him not to. Her policies are turning out not to be very good, so I may jab him a bit for that. To be fair they did talk about the 2008 election and the 2012 election in the US. My BIL thought Hillary Clinton was going to win the election and I set him straight early on (I was right about that too).
We just had an election about a week ago and I prodded all my students to vote. I was able to vote in Korea for the first time.
There used to be day tours over to Kaesong in North Korea before things got really bad the last couple of years. One of my friends from the US went and took photos. I wanted to do that, but as relations deteriorated they canceled the tours. I'm not so sure I'd do it now that Kim Jung Um is in power. My FIL was born in what is now North Korea in a village outside Pyongyang.