Except triggered lights that can be turned ON/OFF we can use a default Light, read well, a Default Light with Corona set and sitting inside Lamp (non-solid a la EPIC).
Okay, but default Light will not react at triggering and neither if we are using some "PropertyChanger" because of replication problem. I'm saying: This is not an issue, is an advantage, we are using a trick for turning OFF corona having the same effects ON Line and OFF Line using... A SMALL MOVER.
Coronas are not visible through doors so... we are just closing a sort of door over this light - corona will get turned off right inside lamp - not visible. Of course, we can use something written in MyLevel if we want Initial dark area. Mover after 1 second (or less) will cover light making things to look as expected, in purpose to have spectators entered figuring things as desired. Mover is exactly like TriggeredLights - a TriggerToggle type.
Secondary option is porting Corona Light with Mover outside of player visibility -> bStatic=False, bMovable=True and probably will bCollideActors if it needs to... Here I set an AttachMover (previously tested).
Does this even work ?
Yes, let's see this small sample because talking too much is useless and not productive. Trigger is visible in center and it is being set a bit more cute than is in default setup, for preventing a multiple triggering operation.