A question for the tower controllers in YSSY. Do you know if someone who wants to blastoff during curfew has a dispensation or do you just have to trust the pilots? I find it strange that the tower would let you TKOF knowing that it is breaking the law.
Aircraft are advised that penalties may apply, and then they can depart if they still want to go ahead. ATC's lost the ability to stop aircraft a long time ago. It's up to the captain.