A one-point "behind" is scored when the ball is kicked over the behind line extending between the central and outer goalposts.
If any part of the ball is on or above the goal or behind line, it has not crossed the line, therefore the ball is still in play and a score should be registered.
Glenn Metcalfe saved Scotland early on with touchdown on behind line.
If the ball has passed over the goal or behind lines and the field umpire gives the "all clear", the duty of the goal umpire is to register a score.