Well, maybe the lesson there is that you are subject to warrantless search when on other people's (or govt) property. I don't think kids are under the illusion that they own their lockers...
The answer is no, I'm not (at least in theory; there are so many exceptions that you really are).
Moreover, you're not required to enter "other people's (or govt) property". Kids are required to go to school.
The reality is that students have been shafted by the Supreme Court ignoring what the Constitution says.