This is true and also mostly unhelpful. It's possible to build a car without a muffler. Does that mean it happens often enough that we need to dedicate a whole

This is true and also mostly unhelpful. It's possible to build a car without a muffler. Does that mean it happens often enough that we need to dedicate a whole pooh-pooh session to the possibility? Is a manufacturing process not more likely to be useful if it prevents this error from ever occurring?