[kotojo]

From a bit of a ways into the article

"Ahn says she would like to see penalties for parents who make unfounded accusations against teachers or practical measures put in place so that mandated changes can be adopted in classrooms, such as removing a disruptive student elsewhere to allow teaching to continue."

So, it seems like they don't even have the power to make a student leave their classroom without fear of retaliation at the moment.

[kijin]

If you send a student somewhere outside of the classroom, the parents can argue that 1) you deprived him/her of educational opportunities; 2) you mentally abused him/her by sending her alone into the dark, scary corridor; and 3) you damaged his/her self-esteem by doing this in front of all the other students. If the parents are in a particularly vindictive mood, they can probably get a psychiatrist to back up their bullshit, too.

None of these charges are likely to stick under the revised legal framework, but the mere threat of a lawsuit can be tremendously burdensome to a young teacher just out of college. The teacher who committed suicide in Gangnam last summer was only 23 years old.