Years ago I was in the emergency room waiting to get stitches, and a man stumbled into the waiting room bloody from a four wheeler accident up in the mountains.
He had driven his truck down from the California Sierras into the Central Valley because he had seen an ad on TV for the hospital in my town and he only wanted the best treatment. The guy was delirious, and had been in no shape whatsoever to drive for several hours down high mountain roads, at night. But he said it was okay because he "had the cruise control on."
Here's the moral of the story: some technologies in cars today encourage really bad behavior at the wheel. I'm not saying that cruise control is particularly bad (this is the only instance I've ever heard of it being used recklessly), but some features like lane departure warning systems only seem to encourage people to take their eyes off the road, or drive when they're exhausted thinking that a seat buzzer will save them from drifting into oncoming traffic. A study from one of the Institute of Highway Safety's divisions backs up my strong feeling.