[header] How to stop parents knowing about an after school detention [title] Get home first. [step] Most schools tend to send a letter home to your parents, explaining about your detention. If you happen to be one of those schools, try to get home every day before your parents do. 
That way, you'll be able to check the mailbox for any letters from school that will drag you into the danger zones. If you do find a letter from the school, dispose of it immediately.