Harsh? Worth booing? Fair to shake a head?

Jamie Roberts of Wales runs with the ball. David Wallace and Brian O'Driscoll grab him and bring him to ground. As this tussle goes on Wallace clings to the ball. When Roberts is on the ground, Wallace is still clinging to him.

The referee penalises Ireland.

The home crowd, boo, the commentator believes it is extremely harsh and O'Driscoll shakes his head to confirm suspicions that the referee was wrong.

The referee refers to a "clarification we had this week". This refers to a ruling by the International Rugby Board on the tackle. Ironically the clarification was done at the request of Ireland. Ireland asked, Ireland received an answer but it seems that Ireland did not get the message to the players.

The clarification referred to was sent out on 10 March, just three days before the match. It came in a ruling from the IRB. A ruling is not law but has the force of law.

The ruling stated: Players who were attached to the player who is tackled and who remain on their feet must release the player and the ball (Law 15.6 (c)) and then may play the ball in accordance with Law 15.6 (b).

This refers to Wallace. He had to release Roberts and the ball.

Law 15.6 OTHER PLAYERS
(c) Players in opposition to the ball carrier who remain on their feet who bring the ball carrier to ground so that the player is tackled must release the ball and the ball carrier. Those players may then play the ball providing they are on their feet and do so from behind the ball and from directly behind the tackled player or a tackler closest to those players’ goal line.
Sanction: Penalty kick

The referee was right. Sadly in this complicated game the referee often gets more flak when he is right than when he is wrong. Perhaps because there is in rugby football - and other games - an instinctive distrust of referees.