Let me make a hypothesis first! Suppose your parents agree to let you stay outside. Suppose you are a poor student, then your family is a poor family. Your family holds the government's subsistence allowance every month, so your family must have a certificate similar to that of a poor household. Or those who meet the application conditions of poor families can apply to relevant government agencies. Take this certificate to make a copy, and then go to school to apply for detention with the copy and parental consent.

In fact, the school just needs a convincing reason. As long as you have sufficient reasons to apply, the school will not refuse the visa, nor dare it. There are other reasons such as special diseases, and you can apply if you have documents to prove it. Just like the documents of poor families.

It's up to you whether you have these documents or whether you can get them.