The rule allows teams to challenge the referee during a break in play if they feel a wrong call has been made and can be used twice in a match by each team, once in each half.
Of the successful White Cards used so far in the FNB Varsity Cup, 57% have overturned a foul play decision, meaning that dangerous and early tackles are being clamped down on thanks to the use of technology.
One downside of the White Card is the time it takes out of the game, which can disrupt the flow of the game.
This season, the average time it has taken for a White Card referral to be made is a minute and 57 seconds, compared to the one minute 29 seconds for referee referrals.
Duitser Bosman, CEO of Varsity Sports, believes, however, the White Card rule will improve the more the system is used.
It is important to consider the nature of decisions being referred because with a large number relating to foul play, it is natural that these decisions will take longer.