Does this work?

I saw this ad for a light control in one of those mail-order catalogs. 
Now I am not a rocket scientist, but how does this thing work?
 

Let's see. . .
1. It is dark out and the bulb comes on.
2. Since the sensor is inches from the bulb, it will now think it is light, so the lamp will go off.  
3. Then since it is dark, the light will logically come on. . . .??? 
4. Since it is light, the lamp will turn off. . . .???