Posted Jan 26, 2013 12:42 UTC (Sat) by nijhof (subscriber, #4034)
[Link]
When switching a light switch, you see whether the light is currently on or not, so switching will always change that, so no label is needed.
For added fun maybe one could add a multi-way switch ("hotelschakelaar") to the GUI, where effectively the on or off status is an XOR of all the switches..
(certainly in my house I knever know which switch will turn which light on or off: most of the time there are three switches together in some random order compared to the topology of the rooms, half of which are multi-way)