They allow overnight here in one particular lot. No one likes parking there, it's a hike and shuttles don't run that often midweek, so plowing that first in the evening probably enables parking there overnight. (I notice now they've moved it to a new, very small lot, which will signifantly reduce available spaces.) Then is a fee these days and a limit on # of nights. The specific place, fee, and limt have all come on gradually as visitor counts have increased, so I have to assume acceptance of it was tied to encouraging visits and now they don't need has much. Although most of the area is on forest service land, that lot certainly is not.