our teacher was telling us about vending machines in japan, and he said that a lot of them, while convenient, were able to ruin your reputation if you bought from them, e.g. those selling cigarettes and other taboo items. for example, if a student bought a packet, likely someone would see, tell their family, ring up the school, have it on their permanent record - effectively ruining their chances of getting into a decent uni. all over a packet of cigarettes!
in regards to kaiwa, we have weekly practices, but they're really only for our detailed study now - kaiwa was last year, though i could do with more practice, since i'm not very good at spontaneous discussion. we also do this thing where we stand up in front of the class and have the the other students ask us questions, while we get filmed and critiqued to see where we're going wrong.