Do you have a link? I'm fairly certain the supreme court has ruled that school administrators take the place of parents while school is in session and are legally able to search and question students without a parents permission.
Yes essentially government (not private) schools are considered sovereign grounds, and if you participate in school activities (as in if you are a student) you have waived a number of rights.
When I was a senior in high school some square snitched saying I was selling cannabis on the grounds over a disagreement of a personal nature. But I had a few things in my favor, one I was a top student in the top 10 of out 50 in my class. They give good students much more slack, and second of all I tightened up quick. Treat administration as you would a police officer, be polite and don't say anything incriminating. Answer questions to the best of your ability but do not volunteer any information. If things get real hot simply say "I am no longer comfortable speaking without representation from my legal guardians." and all they can do is search you. Clam up and wait for your parents to come ream them a new one. You'll be in hot water but you would be in even more hot water if you happened to have legal issues. And some school if you deny a search there is a mandatory suspension period or even expulsion. Review school policy.
Although some states have a search provision, listen carefully if they ask to search your person YOU CAN DENY IT but prepare for the shit storm as you
may or may not be arrested if there is enough suspicion and they can search you and your possessions then. But they may ask you to empty your pocket's and your bag, that is a sign they don't have enough evidence but also can depend on state law. Asking a student to empty ones pocket's and bag is not considered a search as it is voluntary. You can deny it but depending on state law they may attempt an arrest and then you are in a bad position. If you happened to be an idiot and took stuff to school with ya and didn't stash it well, such as say the lining of a backpack or a hollowed sharpie marker well no good is going to come of it, but if ya gotta empty your pockets and bag if the stuff is stashed you may be fine. Third if ya really gotta smoke at lunch or before school or after school...
find someplace safe to stash the stuff at least 1000Ft away from the school. Also known as the end of the school zone as penalties double for drug offenses within a school zone.
Bottom line(s): Number 1 know your local law the library has tons of reference books. Number two never take drug's to a controlled environment such as a school, college, mall, state fair, post office or any federal building or any building that uses security on a frequent basis. Stash it somewhere safe if ya really really really need it around. (for example perhaps I may have had a false foam rock I kept mine in behind the grocery store I stopped at every morning before school)
Finally and here is the big one... if you are using cannabis to have a good time and you don't have a legitimate medical use...
LAY OFF till you are 21 at least and 25 if you can. Cannabis use does slow brain development, and is far less dangerous if used when you are done growing.