Ça rigolerait pas properly translates what you want to express. Parking enforcement would be taken seriously so violators would feel the pain.

That said, while a native French could have been the author of these sentences, note that different levels of languages are mixed in them:

Franchement, qu’est ce qu’ils n’ont pas compris… : standard spoken French

qui font fi de toutes les règles : formal/literary

Si j’étais à même… : formal/literary too

coller des contraventions : casual

ça rigolerait pas, moi je te le dis ! : colloquial