Fixed the link - sorry about that. Also, according to this Yonhap article I just found, the arrests took place in Cheongju on September 7, 2004. The writer of the article linked below, Jason Storbakken, is mentioned in the Yonhap article as 스토바겐(27.미국)씨. In his story, he mentions that he and his three friends were part of a group of 15 teachers who were arrested, though the Yonhap story mentions only 12 people who were arrested. At any rate, it's interesting to have the story behind the story of this Yonhap article, though it's certainly not the first piece of writing about being arrested for drug use in Korea.
While looking for something else I stumbled across this story from 2005 by an English teacher who was arrested for testing positive for THC. As a result, he spent two months in jail waiting for his trial, and had to pay a fine before being deported. I found this interesting:
We were returned to our cells at the Sondong Detention Center and a week later brought back to court for sentencing. The judges said Adam and I had to pay $3,400 (reduced from $5,000 because we had served two months), and be deported. Our sentence was slightly harsher than Felix’s, because he had not yet acquired his educator’s visa, while we were officially teachers.[Emphasis added.]You'd think there would have been more repercussions due to teaching illegally, though perhaps the police did not realize this (it does note that 'Felix' had to serve out his sentence because he couldn't pay a fine, and it seemed to be more than 6 months). It's interesting that those who were 'officially teachers' got a stiffer punishment than someone who was not, perhaps commenting on the higher expectations of teachers in Korea (note that this took place before the English Spectrum incident).
On another note, the slow police reaction to the 'riot' he describes at Hwaseong Detention Center isn't very encouraging.