They're not. Their licensing agency sent them a bill; they didn't file a lawsuit. Also, it was a PTA, not a school board.
Also, they're not trying to collect anymore:
Disney C.E.O. Apologizes to P.T.A. Asked to Pay After ‘Lion King’ Screening - link: https://www.nytimes.com/2020/02/05/us/lion-king-berkeley-mov...