Go read the LBW law. If the ball is hitting the stumps, it is out. The fact that umpires often aren't confident with giving those decisions, or the South Africans wouldn't have considered it plumb enough to overturn, is entirely irrelevant.stupid on field call, Smith was 2m outside his crease. Not out would definitely NOT have been reviewed. i rest my case
Smith can count himself unlucky because of those factors, certainly. But the decision was not stupid; it was literally proven to be correct.