Hi guys. I think that the surface book is spending energy to maintain electromagnetic connection between it's tablet and keyboard.
Additionally it is monitoring when you press the docking button.
Even if it's on shutdown.
This is the main difference between conventional laptops and our ’miracle’.
The connection is not electromagnetic. The magnets in Surface Book are permanent ones. The tablet is held by a mechanical connection which is released by applying current to muscle wires (yes that's what they are called). The button I'm not sure about but
there is no reason for it to be powered, it only needs to complete a circuit when pressed.