[Miranda_]

If you don't want to get detention, then don't break the rules. It's fairly straightforward. In any case, school punishments like writing lines or having to stay after school are to teach you the consequences of your actions; ie, what happens in the real world. If you throw chalk at a policeman, believe me you'd get a lot worse than having to write, "I must not misbehave" twenty times. O_o