Detention notice for the mother of a student.

In this warm up for the day, it is a notice to a mother of a student just letting her know that her son has detention on Friday. The teacher gave the student detention because he contradicted her with "disregard for authority." The only reason the student did so is because the teacher said one kilometer is more than one mile. The student refused to agree with this and knew he was right and she was wrong. He also said that she is lyling to the class and told the students not to believe it. Personally i think this student deserves nothing. There is no reason why the teacher should have to give the student any punishment. He can state his own opinion to who ever he want no matter what it is. THere is simply no reason that the teacher should be doing this, and she is sending wrongful info to student. There has to be something in her teaching license where she cant teach false info. I do not agree at all with this letter.