As an aside its common to prewire items on many different cars where the option that would use that wiring is not actually installed. Its a bean counting thing. It can be cheaper to build with wires unused on some models than manage multiple stocks and their eventual installation if it differs. From the OEM standpoint it doesn't matter anyways. They count costs down to the penny for every car and the cost of that unused wire is reflected in the price across the model line.
2012 E92 Space Grey with fox red/black/black, comp, premium, DCT, premium sound, sirius, heated seats.