Clip 3 - 3 May 2017 - Law 20
Too many in the front row.
The Cheetahs put the ball into the scrum and the Stormers put pressure on them. On the Cheetahs left Oupa Mohoje (7) slips up to join the prop, Charles Marais. The referee is on the other side. There Paul Schoeman (6) of the Cheetahs moves up onto the prop and then gets under the Stormers loosehead Ollie Kebble to counter Kebble's pressure.
The referee penalises the Cheetahs, saying: "Flanker No.6 coming in the side, becoming four props."
The truth is it happened on both sides but more obviously on the side where the referee is, which suggests that the commentator, a former international prop, was right in suggesting that it was common practice but unpenalised.
Law 21.1 (e) Number of players: eight. A scrum must have eight players from each team. All eight players must stay bound to the scrum until it ends. Each front row must have three players in it, no more and no less. Two locks must form the second row.
Sanction: Penalty kick
The referee was right.