Sending the parents a bill under this condition is roughly the same as the Chicom practice of sending a bill for the bullet to the family of folks they execute.
The law does not mandate that the child attend an after-school program, which is where she was when the tantrum occurred. She seems to have been there for the convenience of the parents.
Most states provide exceptions from the mandatory attendance statutes for severe illness or handicaps. Most schools and states did not accept severely handicapped or mentally ill students until the courts forced them to do so.
There are a number of students for whom the school is essentially a very expensive day care system.