I'd go along with the ones asking, what rule did they break?
I've flown in and out of closed airports quite a lot... we just needed a permission by the management, which we had for all the airports nearby, the agreement was for a year at a time (except one where the authority required a manned ATS unit open when using the airport).
There could be some regulatory requirements with regards to fire and rescue or ATC availability for the particular flight... besides that....
Even filing a flight plan, giving the centre a phonecall for a clearance, or departing up into uncontrolled and the pick up an ATC clearance in air is also an option.
I once had an ACTO stating that I needed lights on the runway when arriving after sunset (in twillight), which is correct, but not a requirement if ATC was not established.