Korean Group Pay Concept
If you are planning to go to a special event, a trip or an amusement park in a large group, Koreans often give their money to one person in the group to manage. This person will then use the pool of money to pay for everyone during the group activity.
Of course this is not a perfect system. If you are the type of person who expects every cent to be accounted for, and your contribution to be spent solely on yourself, then you are likely to be disappointed.
It is custom that at the end of the activity, the remainder of the money is used to buy food or some simple items to be distributed evenly among everyone involved.