The Brumbies had been reduced to 14 men one minute earlier when prop Ben Darwin was shown a red card for his second yellow card offence.
Danny Guthrie saw red for a second yellow card after the break, allowing the hosts to ease to a comfortable win.
"Some schools have a yellow or red card system and I have known members of staff criticised for over-using the red card, " he said.
Two London hospitals - Bart's and the Royal London - have already introduced yellow and red card systems to warn abusive patients that treatment could be withheld.
Hart escaped either a yellow or red card for his infringement then rubbed salt into Chelsea's wounds by saving the resulting penalty from Frank Lampard, denying the midfielder his 200th goal for the Blues.
Referees can only compile a report to the Rugby Football Union if they have issued a yellow or red card, and as that was not the case with Fenn's injury, there appears little more that the official can do.
It says start at red, which I interpret as meaning you don't have to give a red card, you can give a yellow or less as well.
Stokes converted the penalty to double his own personal tally, with Celtic fans left wondering why Langfield was shown a yellow card rather than red.
In the 77th minute Pongolle was put through clear on goal but was hauled down by Anthony Gardner, who was inexplicably shown a yellow card rather than red, and then the striker set up substitute John Welsh whose shot was close.
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Two yellow cards lead to a red card and expulsion from the game.
Irish FA officials had feared Healy would be banned for three games as it was thought he had been shown a yellow card and then a straight red.
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Having been shown a yellow card, rather than a red, Kiraly retreated to his line, only to see Arteta curl a superb free-kick over the wall and past his dive into the top left-hand corner.
What happened next, was downright remarkable, though maybe it should not be: Alvarez Izquierdo made a beeline for him and showed him a second yellow, which, of course, equates to a red card and a sending off.
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"In Scotland it was a yellow card but in other countries it would have been a red, " said the Moroccan international.
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"My initial reaction was the foul was a free-kick or a yellow card but it didn't seem to me a red, " said Coyle.
The Germany winger was shown only a yellow card for the tackle, which could easily have resulted in a straight red.
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