Nuclear power plant controls.
Many, many moons ago, a friend had interviewed [link|http://www.foxboro.com/|Foxboro], which at the time did work on the controls for nuclear power plants. He was told that all controls knobs and switches could not and did not in fact do anything directly. The changed state of these controls was sensed and interpreted buy a computer program that would evaluate the appropriateness of the request and act on it if it was reasonable.
For one thing, this prevents someone doing away with himself in a "blaze of glory".
