To answer some of the questions...this is remote with a PIC and an RF link.  PIC detects the event and transmits via the RF link to mother an tattles.  So video is out of the question, or a pilot light.  It has to detect and report.
   
  Optical maybe, but may be  in a dark enviroment to begin with and can't depend on the plug
  size to block.
   
  Torroid or inductor...same issues I am thinking with the hall sensor.  Difficult to the measurment sensitivity over the range.
   
  And, as far as something plugged in and not on...not the case.  Whenever a device is plugged in, it will be on, yet may not be pulling very much current.
   
  Mechanical may be the best.  If I could find a AC recpeticle that the blades touched when the device is unplugged, and opens when the device plugs in.
   

       
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