Quoted from clg:
The issue is the electrical components. What if bad code locks something on. Best case bad fuse worst case a fire.
What you're talking about is basically a specialized case of product liability, where the product is software. In the product liability space, negligence is used for design defects on the theory that greater care in design would have prevented the problem. Manufacturing defects are evaluated according strict liability, because they happen no matter how careful a manufacturer is, and making the manufacturer liable spreads the cost of defects. If a software defect gets someone hurt or destroys property, there could be tort liability—but there's probably that already.