These idiots just never learn that Korean customs inspects the military mail and many people have been caught and arrested for mailing drugs into Korea:
Prosecutors on Wednesday arrested U.S. soldiers and their Korean accomplices for smuggling bags of philopon methamphetamines worth 13.6 billion won ($11.9 million).
Suwon District Prosecutors’ Office arrested an American private, 20, and two Korean-Americans for infringing Korean narcotics laws. Prosecutors also booked without arrest another American private, 20, stationed at K-6 base in Pyeongtaek, Gyeonggi Province, for providing an address to where the contraband could be sent.
They are also searching for four Korean-Americans.
An accomplice in California sent the drugs to Korea in December, prosecutors claim.
They weighed 4.1 kilograms ― enough for 130,000 users. [Korea Times]
You can read more at the link, but I hope they are sentenced to the maximum penalty allowed by Korean law.