Mistakes by sides mean their opponents get the advantage of feeding the lineout and scrums. They get to throw the ball where they choose in the lineout and deliver it into the scrum.
But there is a difference between the set pieces.
If the All Blacks have the throw to a lineout, they decide how many players will be in the lineout and where they want to throw the ball to fit their plans of using ball from the top, to drive and maul or to work some switch move.
The All Black hooker and his targets work out when they want the ball, what decoys to use and whether they want a lob, flat or slow throw. They make the play.
It is different in the scrums. Referees stand in the way near the tunnel while they are still producing a slow call and then making demands along the lines of "okay half" when they think the scrum is steady.
That is a signal for the defending scrum to power up, knowing that the hooker in the team delivering the ball has to strike for possession, reducing his group's collective power.
So much for an advantage in having the scrum feed.
Referees need to stand back and let the teams get on with their own business.
Halfbacks and hookers should be allowed to work on their own systems and rhythms which suit their scrummaging style. They can orchestrate a variety of codes or signals which will suit their timing for the delivery and strike.
Some teams will want to get in and get out of scrums, others will want to engage their rivals for longer.
The team with the ball should make those calls, rather than have the referee go through his ploddingroutine.
He is there to adjudicate on breaches of the rules, not to instruct teams on how they should play.
The All Blacks have not been comfortable with the scrum law changes and that will be putting heat on scrum coach Mike Cron, who was on the IRB committee which went through all sorts of theories until it settled on the new format.
Will Hansen's jaunt across the Channel this week have changed anything? Will he and others in the room have come up with anything that will change the scrum fortunes on the rest of the tour or through the Six Nations series?
Eyes will be on Jaco Peyper, who is controlling the test tomorrow in Paris. If he does make any tweaks, will the public be let in on the secret or will there be more obfuscation?