I agree with Jason's assessment.
I was in Japan many, many years ago and there were vending machines for a lot of things that would surprise the average "westerner". From Alcohol to ahem... Women's underwear and porn (the Japanese versions... some will know what I mean). Signs on them said that they were strictly for adults. At first it seemed odd to me, so I asked a friend that I was staying with, "What's to stop a young person from just going up, putting their money in, and buying the stuff?" I got a look of utter confusion and a response that matched... "They're not supposed to, so they don't!" Initially I laughed to myself and thought "yeah... riiiiiight..." but as time went on and I was there longer and longer I realized that he was RIGHT! They're not supposed to, so they don't!
There is a huge difference in living in a homogeneous society and the melting-pot... now a "salad-bowl" like society is in the U.S. The Japanese have this inherent attitude of "we're all in this together" that I've gotten from every level of their society... from Hiroshima survivors to corporate CEOs, from Sempai to Kohai, from Politician to Clerk... if you're Japanese, you're part of it and you belong. If you're not Japanese, it takes some time because you need to be "known" and accepted... but once accepted, you're part of it and you belong. (although I've heard mixed feelings about whether a gaijin is ever truly completely accept... for me, I felt included after a certain point. Probably when I was given a family wakazashi that feeling became complete...)