Offside.

This is one which has caused a problem for players and spectators for years and years.

Sarel Pretorius, the Cheetahs' scrumhalf scurries back, picks up the ball and kicks it high. He chases but the referee penalises the Cheetahs for being offside. Pretorius is ahead of several of his players but they are still penalised.

The Cheetahs' forwards stood still, Frans Viljoen with his hands in the air to proclaim his innocence, The Cheetahs  were only a metre or two ahead of the place where the ball came down and was grabbed by Karl Lowe.

What the referee says is right.

If the Cheetahs had kept retiring, i.e. going back to their line, they would have come onside when Pretorius passed them. When they stood still  within 10 metres of the ball coming down, nothing and nobody could put them onside.

11.4 OFFSIDE UNDER THE 10-METRE LAW
(a) When a team-mate of an offside player has kicked ahead, the offside player is considered to be taking part in the game if the player is in front of an imaginary line across the field which is 10 metres from the opponent waiting to play the ball, or from where the ball lands or may land. The offside player must immediately move behind the imaginary 10-metre line or the
kicker if this is closer than 10 metres. While moving away, the player must not obstruct an opponent.
Sanction: Penalty kick
(b) While moving away, the offside player cannot be put onside by any action of the opposing team. However, before the player has moved the full 10 metres, the player can be put onside by any onside team-mate who runs in front of the player.

Law 11.5 BEING PUT ONSIDE UNDER THE 10-METRE LAW
(a) The offside player must retire behind the imaginary 10-metre line across the field, otherwise the player is liable to be penalised.
(b) While retiring, the player can be put onside before moving behind the imaginary 10-metre line by any of the three actions of the player’s team listed above in 11.2. However, the player cannot be put onside by any action of the opposing team.

Law 11.2 BEING PUT ONSIDE BY THE ACTION OF A TEAM-MATE
In general play, there are three ways by which an offside player can be put onside by actions of that player or of team mates:
(a) Action by the player. When the offside player runs behind the team-mate who last kicked, touched or carried the ball, the player is put onside.
(b) Action by the ball carrier. When a team-mate carrying the ball runs in front of the offside player, that player is put onside.
(c) Action by the kicker or other onside player. When the kicker, or team-mate who was level with or behind the kicker when (or after) the ball was kicked, runs in front of the offside player, the player is put onside. When running forward, the team-mate may be in touch or touch-in-goal, but that team-mate must return to the playing area to put the player onside.