So, for the sake of argument, assuming she was exempt under the Americans with Disabilities Act, and the police were ultimately wrong to arrest her (presumably she had explained that exemption to the officers as opposed to just asserting she was entitled to disregard the facility's posted policy)... does the Americans with Disabilities Act entitle her to resist arrest?
Let me guess. You already know the answer to that question.
No need to explain the ADA to anybody, they are obliged to know the law. Do you really think you could successfully defend an ADA claim based on the argument that a school district was not aware of their obligation under the law?