Hi, Brendan! I am not so sure with my information, but as far as I know, Japanese passport holders can easily get to China and Korea without being required a visa as they are exempted. A lot of Japanese travel to the places you mentioned over the weekend usually for business or for leisure. Given the short distance, I think they can be common destinations for short weekend trips.
For your second question, I personally think that’s not silly at all! A fan got to do what a fan got to do, right?