Yes, this does work. Along with making sure the class in which the light resides is active, make sure it is in a layer that is active for that viewport also. I have separate classes for SE, SW, NE, and NW lights and turn them on or off depending on the elevation. The many levels of control in VW is its power but if you're not careful they can get out of control. Lighting is tricky, and I certainly haven't mastered it yet.
You can control the visibility of a viewport directly with the attributes palette instead of putting it into a class other than "None". The new viewport class may get inadvertantly turned off and you might not know why it's dissappeared. HTH