In general, local laws typically superseded maritime laws. Rarely however do local laws conflict in this regard, and usually it's local laws will be a more strict version of the maritime law (such as environmental restrictions). Where this might not hold up is if the vessel was in international waters (more than 12 NM from the Italian coast) then the Italian laws would and could not apply. Then it just becomes a question of access to Italian ports, which isn't guaranteed. I'm not sure how they could be fined however if they were not in Italian jurisdiction and didn't break any IMO law.