There is a particular focus on discipline under Joe Schmidt. Giving up penalties results in lost territory, lost points and lost games. With 17 penalties conceded over two matches, according to Opta, Ireland and New Zealand lead the early discipline stakes, with France's 30 at the other end of the scale. But taking the tournament as a whole, is rugby's punishment system being applied fairly?

The post-match disciplinary scoreboard is worth a look. Two Fijians and a Romanian have received one-match bans apiece for dangerous tackles. Argentine lock Mariano Galarza earned a nine-week ban for making contact with the eye area of New Zealand’s Brodie Retallick. It might well be noted that Galarza had been on the pitch as a replacement for Guido Petti Pagadizábal, the Argentinian try-scorer who was replaced after making cranial contact with the boot of Dan Carter as he dove over the try-line.

On more high-profile teams, some have been more fortunate. England's Tom Wood received a citing commissioner's warning (equivalent to a post-match yellow card) after his boot struck the head of Welsh fullback Liam Williams with significant force during Saturday's vital pool match at Twickenham, leading to the player being stretchered off.

It seemed clumsy rather than intentional and, as is the fashion of the time, the two men have engaged in some public back-slapping on Twitter. But swinging a boot in the vicinity of a player’s head is not to be trifled with. Concussion owns a bright spotlight.

Last week Leinster’s Kevin McLaughlin, at just 31, became another in an unfortunate line of players advised to retire from the game due to head knocks. The last thing the game needs is extra concussions brought about by reckless play.

Sent skywards

Wood had been sent skywards in the first half courtesy of Dan Lydiate, the strapping Welsh flanker who tackles so low to the ground as to often have an effective operating height of approximately 14 inches.

For once the master of the chop tackle got his timing wrong, sending the Englishman head over heels through the air. No grasp, and a shoulder directly to the knee. After a review by the TMO, the referee gave a penalty only.

Away from London, there was the case of South African Francois Louw, who upended Samoan scrum half Kahn Fotuali'i at Villa Park.

In the 73rd minute on Saturday, replacement Springbok hooker Schalk Brits carried towards the Samoan line but was stopped five metres out. First man in to compete for the ball was Fotuali’i.

Brits's team-mate Trevor Nyakane then arrived to try to clear Fotuali'i out. Louw then arrived, grabbed the Samoan scrumhalf's leg and propelled him into an involuntary cartwheel. The crowd reacted immediately; referee Wayne Barnes was looking directly at the ruck. The whistle blew, but against Brits for holding on. "Just be careful with the clean [out] as well," said Barnes to Louw.

When a Fijian who tips a player in the tackle but realises what’s going on and tries to rectify the situation still gets a match ban, what of a South African who upends a player in a ruck who’s being held by a team-mate?

The benefit of the doubt does not seem to be applied equally across nations.

In the good news side of the ledger, after a bothersome first weekend of lengthy TMO stoppages, things seem have settled down a little. We’ve also seen the overdue arrival of split-screen replays showing multiple angles at once. Good for the tournament and those watching at home, if not for Ireland and Simon Zebo, who had that marvellous try disallowed.

That opening weekend had seen the TMO in use 25 times in eight games (according to Prozone), a rate higher than any major international tournament of the past 10 years. That rate has cooled down a touch, thankfully, and we’ve since had two matches without the TMO being involved even once. But based on the numbers so far, rugby’s expanded TMO protocols will ensure the final total will be higher than the last two World Cups combined.

Imperfect

The TMO system remains imperfect. As Wembley switches from record-breaking rugby host to welcoming the NFL’s Miami Dolphins and New York Jets, it’s worth noting that gridiron encountered similar frustration in its early days of replay. Having had it in place from 1986 to 1991, owners voted the system out of the game until it returned in 1999 in a new and mostly challenge-based form.

There’s nothing wrong with some thoughtful soul-searching in the quest towards balancing sporting justice with entertainment.