Well, I've never heard of a student getting detention for calling their teacher by a nickname, that would be unnecessary and a little over dramatic, don't you think? I think if the teacher doesn't like being called said nickname then the teacher would tell the student to stop calling them by said nickname. But if the student has done it multiple times after the teacher has asked them to stop, then the student would be punished by being sent to the E.R for an hour each day depending on how long the teacher wants you in there (my school's room for students who have done something bad, like a reset room). But detention? That would just be silly.