For example, if you are caught vandalizing school property or caught with drugs or weapons on school grounds, you can be punished even if the acts occurred outside of school hours.
Additionally, if you post threatening or inappropriate content online, even if it is not directed at the school specifically, the school may take disciplinary action if they believe it creates a hostile environment for students and staff.
Each school has its own policies and procedures regarding off-campus conduct, so it's important to be aware of these rules and understand the potential consequences of your actions.