They were designed to save money, because nobody would forget to turn off the lights. They did an excellent job of keeping people in the dark, partially because of the above sensor problem -- typing on a keyboard doesn't provide enough movement to trigger the sensors -- and partially because of their incredibly high failure rate.
At about $50 per sensor module installed, they had to keep an electrician on full-time replacing sensors. I heard that eventually they stopped relying on trouble tickets and just swept the building over about a two week cycle.
Meanwhile, people bought lights that they could control by themselves. Many of them were halogens running on 150 to 450W.
Failed all the way around.
Since we're already using a Raspberry Pi for other purposes, I have the project of decoding the remote's protocol and driving an infrared led from one of the RPI's GPIO ports.
There are few things as annoying as that.