Out my way, such illumination is part of the state building code.
The stairwells not only have to be on 24/7 -- but they have to have bug-eyes with battery back-ups, too.
Further, the elevator code requires 24/7 illumination at EVERY floor that the car opens on... right on out to the street....
Public spaces are not permitted to go dark since, unlike a home, it would be a rare person who knew their way around without illumination.
