It's been 3 years since I was in Korea (pre-KOtR website!), but at the time, sport was all most Koreans wanted to do. Think steep overhanging limestone. A dozen draws (maybe a few long slings) is a sufficient rack. A gri-gri was the preferred belay device (I was a little picky of who would belay me-- you might observe a partner's technique in advance!)I brought my whole rack-- in 3 years maybe did trad twice and aid once. This time I'm bringing my recommendations above, plus rope, harness, chalkbag, etc. ..
Koreans are group oriented. . . I have even borrowed shoes when I blew out a pair on a trip (got athletes foot). . . but beware, if you are with a group, people will feel free to use your rope if you leave it out (or smoke your cigarettes, etc). Of course, you can do the same. On weekends in a busy area it is common to leave draws up all day because of the convenience. At the end of the day, clean a route and everything finds it's way back.
Things do get back-- I left a blue North Face jacket at the Anyang Wall when I was still pretty new. . .I actually got updated on where it was as it made it's way back to my gym.
OK, I think that answers some of your questions!