Question: Referees occasionally have to manage the behavior of people on the sidelines such as coaches and reserve players. Should the referee display yellow (warning) or red (expulsion) cards when acting to control unacceptable behavior?
Ruling: The use of red and yellow cards is carefully and clearly laid out in Law 10. Cards are to be used when cautioning or sending off a player. That’s it. They are not to be used as a “crowd control” tool. When a card is shown, that is a statement that a player has contravened Law 10 and that certain sanctions will be applied. Specifically, that there will be a penalty (unless a penalty try has been awarded or advantage has been played and gained) and that the sanctioned team will be a player short for either ten minutes or the remainder of the match.
Question: What is the harm in using cards outside the specifications of the Laws?
When a card is shown, there is an expectation by all, both participants and observers, that the specified sanctions will be applied. That would not be the case if cards were used for the purpose of managing non-participant behavior. The result would be a loss of confidence in the referee on that particular day, and a general degradation for all referees.
Misconduct by non-participants is addressed in the USA Guidelines and in the Disciplinary Procedures, as well as in Geographic Union and/or Conference By-Laws. Use of Red and Yellow cards are not part of that process.