This reminds me of a good example from work: the emergency stop button on an industrial robot. By definition, the customer should not be pushing it. Pushing it means something has gone terribly wrong. But when they push it, they expect certain things to happen and they are unhappy when they don't.
(Your typically industrial robot does not rely on software for safety. However software can make the robot respond more gracefully.)
(Your typically industrial robot does not rely on software for safety. However software can make the robot respond more gracefully.)