I thought that tackle was certainly a penalty, he did bring the players legs to the horizontal, however he certainly didn't drive the player into the ground.
However Joubert seem to make it clear that the yellow card was for not bringing the player to ground safely. It was a marginal call, I give you that.
Back to the Brumbies game Bryce had an obvious spear tackle that to me appeared the player was also driven into the ground, the player was give yellow. If joubert's was yellow, then Bryce's should have been red.
Another of Jouberts marginals was when the Waratah player came up from the ruck to intercept, he was called offside however again it was very close, he seems to start his run as soon as the 9 is in the act of passing.
but 50/50's happen all the time, and some you get, some you don't.
One other small habit I've noticed of Jouberts, when he's waiting for things he puts his hands together in front of him, as if almost forcing his whistle hand to not come up too early. Anyone else notice this? is it a coached trick or just a personal comfort?