I have many friends that live with host families, and none of their host parents reward their children with money if they do well on a test.
Jeju Island has a tradition of cleaning up beaches because they are very important to the culture here due to their beauty and their importance as an entry to an valuable food source, the ocean.
Cleaning up beaches during the first week of summer is directly connected to the environment of Jeju Island. Since it is an island, keeping beaches and the environment clean is very important to many island natives. Most people clean up a beach on their own with family or friends, but many schools and businesses also organize beach clean-ups. A lot of the food eaten on Jeju Island comes from the ocean as well. Because of this, Jeju Islanders want to keep their oceans clean of trash.