No, I see it as something very different. When a teacher takes a note being passed around the room, it is in response to active behavior violation. Reading the note is mostly to embarass the kids doing it and get them to stop.
Reading a notebook while in class is to ensure the student is working on the assignment properly and not day dreaming or drowning. Again, the situation does this in response to behavior, such as the kid staring out the window or at the ceiling. When a teacher does check a notebook, it's the current subject, the teacher doesn't wade through subjects of other teachers.
The teachers' response are specific the issue at hand. The teacher's don't use passing a note in class as an excuse for a body pat down for weapons.
The new situation is where the kids aren't in the classroom and haven't engaged in any bad behavior; they're just walking in the front door. They may have happened to be near an undesirable student.
As to the key issue here, my high school had pay phones which kids used. I never heard of any school listening in to pay phone calls, recording who made them and to what number. The school could care less.
They have no business doing likewise with cellphones except in extremely grave circumstances with a court order. I see no reason they should have access to a student's cell phone for its records.
Except in very extreme rare cases, schools did not bother reading personal entries in notebooks, track a student's associations or telephone calls. My school would not check lockers except in extreme cases. Everybody doodles and some doodling can be pretty bizzare. It didn't call for confiscation.
Indeed, in my day the school literary magazine published some bizarre writings at times; and these were things voluntarily submitted.
In some classes (like science labs) our notebook was explicitly stated to be part of the class and would be inspected and turned in. The main issue for us was to buy a separate notebook just for that class so we wouldn't lose our history notes. We also knew to keep the notebook in the prescribed format and perhaps a little neater than notes we took strictly for ourselves.
In elementary school notebooks were subject to inspection (for neatness, mostly) and we knew that. But in high school and beyond, unless specifically stated, our notebooks were our own private property.
Back in my day schools would threaten kids with bad stuff going on their "Permanent Record". In reality that record was buried in a closet never to be seen again. No more.
With cheap powerful computers the incidents, writing reviews, searches truly become part of one's permanent record, accessible beyond school years, whether legally or not. They could come back to haunt someone applying for a job or a mortgage or college, or add suspicion in a criminal investigation.
public replies please