Petition Fine Teachers Unions for Strikes

Changes were introduced which became effective from September 2013 to discourage parents from taking holidays during school term times. Parents can be fined under section 444 of the Education Act 1996, essentially for failing to provide their child / children with an education.
Why is it then that the Trade Unions are not similarly penalised when they deny the availability of education through industrial action.
Surely such action has a much more serious effect as it affects millions of children throughout the country.
It is, therefore, only fair that any strike action should result in a fine being applied to the appropriate Trade Union proportionate to the number of children affected by such action.