Another interesting aspect of Japan. Actually, this may happen in the states and other rural areas, and I just haven't been aware of it until now. When I was backpacking across the many country roads and small towns of Shikoku, I occasionally came across some unmanned shops. Completely unmanned – no cameras, no people, barely within sight of a house, and its food products waiting to be bought.
If you live in a less-than-urban part of Japan, it's very likely you have seen a food stand with fresh fruits and vegetables for sale, leaving only a small coin box to submit payment. What surprised me most is just how cheap this fresh produce really is: you can buy apples, oranges, and sometimes a bag of carrots for only one hundred yen.
Take advantage of this trust system set up by your friendly neighborhood farmers and enjoy the fruits of their labors. Eat well, and pay accordingly.