Nissan is apparently planning to release a fully "by wire" system with mechanical backup (for now):
Nissan previews production steer-by-wire system
"Turn left, HAL." "Sorry, Dave, I can't do that. Perhaps you could sit down, think about it, and take a stress pill." "I AM SITTING, YOU STUPID SILICON PILE OF C**T." Yeah, there's a backup clutch, but that's only good if the cum'pootah knows that something is wrong and chooses to re-engage it and take itself out of the loop.