In my school, a student who refuses to wear their uniform gets suspended.
Our school is quite strict when it comes to our uniform. If you get caught with your tie off, an undone button or untucked shirt, you will get a 45-minute detention after school.
Sometimes, when a student doesn’t wear their school uniform and the security guard or the discipline officer catches them, they may also be required to do community service or have their ID confiscated. Most of the time, this is done so a student would be a better person that follows the protocols set by an institution, and this makes a student prepared for the real world, equipped with good values.