I'm not even sure what the term is for hitting youself with another persons arm. But there it is and the ref fell for it.
The first game of the Super 15 season sees the first double yellow of the season.
At 1:26 you can see #12 yellow, Ma'a Nonu, go into the ruck from the side (penalty), off his feet/lying on the tackled player (penalty), and use his hands in the ruck (penalty). All of this right in front of the referee (stupid move). This is after the referee has warned the Hurricanes, yellow, about this type of negative play. So now the Hurricanes have to play 10mins a man down.
Now at 2:28 you see #9 blue, Jimmy Cowen, kicking for territory. A kicking player can be tackled no problem there but to tackle you have to use your arms. Simply drilling someone with a shoulder is not a tackle. So #12 yellow coming in on the kick with a reckless shoulder charge = yellow card. At 2:59 you get to hear the referee explain the offense to #12 and the yellow captain.
Now the Hurricanes have to play the rest of the game short. Which they end up loosing at home to a team everyone had pegged as a last place contender.