Recently here in Korea, the Commissioner of the Anti-Corruption & Civil Rights Commission replied that buying your teacher/professor a can of coffee is indeed illegal but it would be difficult to actually punish such conduct (due to its triviality).
In a way, I do understand why the Commission tends to be conservative. They will be to blame should they okay something that ultimately ends up being ruled as illegal in court. (The “mistake of law” defense would surely be invoked!)
At any rate, I still welcome the new law because I see no other way to tackle corruption in Korea. The Commissioner’s comments change nothing. Teachers should not accept any food/gift from their students (or the students’ parents).
It is our duty to, at least, try to abide by the law. Whether it is enforced or not. I find such effort/attitude noble.