Actually it is a lawful reason. The school is restricted public property - it is not open to the public. The school gets to set the restrictions on who can and can not be on the property.
It’s not that simple. Just because someone says it’s a rule doesn’t make it lawful. She and her parents values her constitutional rights. Her rights were violated. She consulted her attorney and determined she was within her right and decided she will not surrender or give up any of her rights. Legal challenges across multiple state court districts have ruled schools cannot require masks.This is not a valid trespassing situation. Schools cannot require masks. US Constitution is not void where prohibited by a school board. Police took an oath to uphold the constitution. Hope you learn something.
Seriously comrade? GFY