Coles, who has quickly risen to be the All Blacks' first-choice hooker due his physicality, pace and ball skills - along with his core set piece roles - was in the spotlight last November when he was sinbinned for lashing out with his foot in the test against England at Twickenham.
His opposite Dylan Hartley was the instigator, as he so often is against the All Blacks and in fact any team he plays, but Coles took the bait and after he reacted, referee Nigel Owens had no choice but to show him a yellow card.
It's this short fuse which concerns many about Coles, especially with a World Cup approaching. Even coach Steve Hansen admitted at the time Coles' discipline could become an issue.
"He fell to a sucker punch didn't he?" Hansen said then. "They were at him for a big part of the game.
"He will learn a lesson, hopefully, because we can't afford in a tournament like the World Cup to lose a hooker for four or five weeks. If he had mistakenly got someone in the chops with that boot he would be home.
"It was pretty dumb, he knows it was dumb and he will learn from it."
And yet, there is also a feeling among those high in the New Zealand game that it's this compulsion to play right on the edge which makes Coles so good, and with the former great Bismarck du Plessis having issues with form and discipline himself, a case could be made for Coles to be considered the best hooker in the world.
The worry is that if Coles tones it down too much - that if it is coached out of him - he will lose that edge and won't be the player he is. It's a juggling act, and with Coles now a fair way ahead of Keven Mealamu and with Nathan Harris considered the third hooker but only now nearing a return following his ankle injury suffered last year, it's an important one for both Coles and the All Blacks.