The consequence, however, can be absolutely decisive - the difference between winning and losing, being world champions or runners up.
There is scope for mistakes in all decisions, but the scrum is fundamentally flawed. It is often impossible to follow (not offend) or apply the laws (identify the offender).
Firstly, the sheer biomechanical complexity and the combination of forces involved means that even the most advanced sports scientist in a laboratory could not isolate the cause of a scrum collapsing, wheeling or "popping up".
If they are uncertain, the referee should reset the scrum but it could mean an infinite number of scrums.
Justice should not be rushed, but players and spectators alike would soon turn their back on a game where scrums proliferate.
Referees are thereby required to act decisively but often the team deemed to have the weakest scrum is penalised.
It certainly doesn't follow that the weakest team is guilty. Scrummaging superiority is often attributed to "dark arts" - dubious and deceptive tactics which force the opponent's scrum to disintegrate.
Even if the referee could be certain that the scrum collapse was a result of one team failing to withstand the pressure from the other team, this does not mean that they should be punished. It may be physically impossible for them not to break the law. The combination of forces on their body means that they are not acting, but being acted upon. Their actions are out of their hands - they are subject to forces that they cannot resist. When a player is singled out as the offender, they are often being punished for an act over which they had little or no control.
The reward for superior skill in rugby should be tries and the scrum is supposed to provide an opportunity for one team to gain possession and attack the open field.
Instead the scrum is a lottery providing a slow ball at best and a sequence of penalties at worst. For teams who are dominant, it is now used as a tactic to get a penalty or a penalty try and potentially to reduce the opposition numbers as a result of a yellow card.
So the scrum as practised today has little to do with justice, fairness or merit and perhaps more importantly for the World Cup, has little to do with entertainment.
Let's hope the decisive score in this year's World Cup isn't the result of the referee guessing who offended.
Carwyn Jones is Professor in Sports Ethics, Cardiff Metropolitan University.