Joubert is widely regarded as one of the best referees in the business, but awarding that penalty could be the last decision he ever makes in a test match. With the benefit of hindsight, and more pertinently slow motion replay after slow motion replay, it is now obvious that Australia should have been awarded a scrum (from which it might well have won the game anyway) rather than a penalty.
It is not in Joubert's favour that he made an even worse call in the final of the 2013 Super Rugby final, costing the Crusaders the title. On that occasion he reportedly phoned Crusaders coach Todd Blackadder to apologise for getting it wrong. Plenty of referees have got things wrong before, but one does not recall any of them apologising.
He also copped criticism for his presiding over the RWC final in 2011, when he apparently should have penalised the All Blacks rather more than he did, particularly in the latter stages of the second half, when one penalty could well have decided the outcome. That will always be a moot point, but two games two years apart, two wrong calls, one rather more obvious than the other, and Joubert's career could be over. That would be a great shame, and grossly unfair. More to the point, while no one cares too much about the Super Rugby title, the RWC quarter-final decision will almost certainly result in greater authority being given to the TMO. And that would not be a good thing.
The problem is that the TMO, even when used only to determine whether a try has been scored or whether there has been foul or dangerous play, slows the game down. It robs the game of its flow, it penalises the fitter team, and it discourages the flair that the best teams can produce.
There has to be some room for human error. Goodness knows we've seen enough of that over the years. In the past it has not generally proved be career-ending, and it should not be in Craig Joubert's case.
Wayne Barnes is a good example of getting it wrong. He and the touch judge, sorry, assistant referee, on the All Blacks' left survived the travesty of Cardiff in 2007, Barnes going on to enjoy a solid if somewhat pedantic career, after his blunder potentially cost the All Blacks the chance to win the cup eight years ago.
Craig Joubert might have cost Scotland a chance to make this year's semi-finals, but looking at what happened without the benefit of slow motion it is not difficult to understand his decision to award the penalty. It has not gone unnoted that he did not have recourse to the TMO in that situation; he might have stood out there watching the replays offered to the crowd before making a decision, but that's no way to referee a game either.
It has been suggested that if that penalty had been awarded in the first minute rather than the last it would have been of no great moment. That's probably true. It might also be true that it assumed huge significance because it killed the semi-final dream of a Northern Hemisphere team. If one might indulge in a little paranoia, it was a Northern Hemisphere team that benefited from Barnes' myopia in Cardiff in 2007, and no one north of the Equator got too excited.
What we are now being groomed for is the TMO playing a much greater role. Perhaps the technology was shown at its best when the All Blacks met South Africa on Sunday morning, in that it exposed a couple of penalty offences (wrestling players to the ground by the neck, a technique that really does need to be expunged from the game), without holding up play unduly.
That's the key. If referees are to make greater use of replays, then it must be done quickly. Australia's NRL offers evidence for that argument week in and week out, to the point where referees are increasingly reluctant to make any decisions at all without referring to the TMO, resulting in long delays. The Northern Hemisphere might not mind long breaks in play while someone examines what happened from every possible angle, but the Southern Hemisphere will, in that, like so many of the rule changes we have seen over the years, it will slow the game down and cost them one of their advantages.
If the rules are going to change before the next RWC in Japan in 2019, perhaps the IRB might also look at making the tournament shorter.
It seems an aeon since England beat Fiji. It's a good thing that there is room for some of the game's lesser lights, or second-tier teams as they are now more respectfully referred to, not least because they must contest qualifying matches to get there, which is good for the game. That builds interest in the tournament over a much longer period of time than is the case for the teams that actually have some prospect of winning it, but it makes for a wearingly long finale.
There's not much to be done about that though, given that the physicality of the game demands at least a week between matches, although the smaller fry were once again called upon this year to take the field with somewhat shorter recovery periods than were granted the first-tier teams. And reducing the final field from 20 to 16 would only shave a week off what must be the longest-running tournament in world sport, so the benefits of making room for the likes of Georgia and Canada probably outweigh the advantages of smaller pools.
It would be nice to see more Southern Hemisphere referees though. We do have some good ones here, in Australia and South Africa, but given the fact that no Northern Hemisphere teams made the semi-finals this year the IRB probably isn't ready to hand even more influence to the New Rugby World, even if some are calling for England to launch a new age by recruiting its next coaching team from the Antipodes.
Imagine what an England team boasting a Richie McCaw, a Ma'a Nonu and a Ben Smith could do, assuming the referee would let them do it.
