Perhaps much of the dark glass is benign, performing routine functions like presence detection, responding to simple jestures, benign infared imaging, and the like, without transmitting any photometric information (images, or the like) elsewhere. Today's generation of smart light switches, smart motion detectors, etc., are often hidden away behind locked doors. It is only occasionally, when doors are left ajar, that we get a chance to take a look at some of this intelligence.
Dark windows and the systems built around them ought to be subject to inspection by those who are "seen through the glass, darkly". Take a look at where automatic flush is used, in high security establishments such as airports, where there is not one square inch of the establishment where you can stand without being "seen through the glass, darkly". These dark panels, with tamper-proof screws, shroud their contents in secrecy, leading to an unhealthy system of absolute trust in those how have installed them.
The restroom of the future is here today at MIT: See this same space in a different, more futuristic-looking light (24-bit color, 147k).