This is not my bet. I was listening to the betfair podcast yesterday and Emmet O Keefe was speaking about how there's a new rule for the tournament that only the captains are allowed to "argue" a decision made by the referee. And he put forward a bet of Over 230 yellow cards for the tournament at 20/1.
Then last night I was looking at Boyles bets for the tournament and they had over 220 cards at the same price, so I stuck a fiver on it. Also took 11/2 for 210 or more cards (so hoping there's a glut of cards in the early stages where players "adapt" to it.