(2) Nina Totenberg, At Supreme Court, Mean Girls Meet 1st Amendment. NPR, Apr 28, 2021 https://www.npr.org/2021/04/28/9 ... -meet-1st-amendment
("The case was brought by a 14-year-old high school cheerleader [the age in 2017], Brandi Levy. * * * off campus — Brandi took a photo of herself and a friend flipping the bird to the camera. She then typed the words at the center of this dispute: 'F*** school f*** softball f*** cheer f*** everything.' 'I posted it on my Snapchat' * * * Brandi was suspended from the [cheerleading] team for the rest of the year. * * * she and her parents challenged the suspension in court, contending that Pennsylvania's Mahanoy Area School District had no right to discipline Brandi for her off-campus speech. A federal appeals court [for the Third Circuit, based in Philadelphia, Pennsylvania] agreed, ruling that the school could punish her only for speech on campus or at school-sponsored activities. * * * But Brandi Levy's case is the only one in which an appeals court has ruled categorically that a student's off-campus speech is not subject to school discipline") (emphasis original).
Supreme Court has ruled repeatedly that students can be punished for ACTIVITIES outside a school.