Many people in Japan/Hong Kong make a good living, but their homes are tiny. So it's common for them to buy one or two luxury bags instead of ten lower-priced ones simply because of lack of space. I wouldn't question their authenticity any more than from anywhere else (but of course, always authenticate and check feedback!). However, as the above poster mentioned, anywhere that is hot and humid and doesn't have air conditioning can make bags/clothes smell musty/mildewy so that is something to watch out for.