I can not find any reference to the reasoning behind this, only references to Law 5 — which do not really address this issue.
Why not (as they do in Water Polo) show a card to a team official or coach? If the Referee is responsible for maintaining control of a game and has the authority to ‘send off’ a team official or coach…why not show the card?
USSF answer (October 15, 2008):
Reasoning? You want reasoning for matters that have been true from time immemorial? Not going to happen.
Law 5 tells us that the referee:
– takes disciplinary action against players guilty of cautionable and sending-off offenses. He is not obliged to take this action immediately but must do so when the ball next goes out of play
– takes action against team officials who fail to conduct themselves in a responsible manner and may, at his discretion, expel them from the field of play and its immediate surrounds
This is amplified later in Law 12 as follows:
“The yellow card is used to communicate that a player, substitute or substituted player has been cautioned.
“The red card is used to communicate that a player, substitute or substituted player has been sent off.
“Only a player, substitute or substituted player may be shown the red or yellow card.”