Parents can face jail time

The Gauteng Province, Johannesburg South Africa, has re-written its education laws, according to The Star newspaper (10 January 2012) "if a parent of any pupil who is subject to compulsory school attendance fails without reasonable cause, and after a written warning by the head of department - he or she shall be guilty of an offence and liable on conviction to a fine or to imprisonment for a minimum of three months.." I guess the question that one can ask - is how do we define "without reasonable cause"?