Even if you send your kid to school with a paper notebook, the staff has always had the legal power to seize and read it. If anything, the school shootings era has expanded that authority even beyond the broad latitude it was granted before: https://www.ascd.org/el/articles/the-right-to-search-student...
(Before replying, please note that I'm not expressing any opinion about whether this is good or bad; it's just how it is.)
That authority has always stopped at the sidewalk, too. Taking computers home has altered the scope of potential overreach, particularly with personal computer use at home and the potential school control of camera and microphone devices.
(Before replying, please note that I'm not expressing any opinion about whether this is good or bad; it's just how it is.)