yes, it feels wrong, but you cannot easily determine what is "enclosed" - the lights are inside bounding box of some object, but not inside the object itself. And even if they were, detecting if one object is inside another if not reliable and frustrating. And if you would use some rule like "do not cast shadows from objects overlapping the light", you would get sudden and counterintuitive changes when moving the light, as it would switch the modes.
So: while second mode is needed, it will be implemented via a checkbox, as I am not currently aware of any automatic sensible way to determine which mode should be used for which light.