How about the 4th amendment rights? There's more than just the first and second.

"Amendment IV

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

"It’s unnecessary, it’s embarrassing for a lot of the students and it makes them feel isolated and separated from the rest of American school culture where they’re having essentially their First Amendment rights infringed upon because they can’t freely wear whatever backpack they want regardless of what it is." – David Hogg