There are 24/7 day stores open and without any employees - you just walk in THE OPEN DOORS (no i.d. needed) any time of day and night and pick up any and all you want, then proceed to the ATM to pay, walk out the open door.
Easy peasy.
But this is South Korea, a hard-working socially-sensitive community of 50-million densely populated people who have a lot of pride (and sense of shame).
No way in hell could an open door to a store full of ice cream, cookies, sodas and other treats survive looting in any part of the Americas.