Thing:
:
Why would your airports close just because it's night?
Maybe because people who have been working there all day might want to go home?
What people? Are you saying there needs to be someone on the ground at the airfield before it can be used? That's a bit quaint!!! What do they actually do that enables an aircraft to fly from that airfield?
Here in New Zealand, like the US and Oz, so long as the airport is equipped with runway lights that are operative you are good to go for night ops. For private ops day or night there is no requirement for any ground based personnel.