I dont think the parliament by itself can set laws, it would need to be agreed to by the Councilof Ministers as well. So unless they're happy with it it wont happen. As for sanctions for not applying the law, fines, holding back of funds. If they dont apply the law or dont follow it they can be taken to the European court of justice. I dont think we've ever had a scenario where EU law has not been applied unless there was an opt out. We may see that tested soon, by Poland and Hungary though.