According to my calculations, this rule means that it will be possible to win a match using just 3 riders, With just 3 heat leaders, it works like this...
Heat 1. Home no.1 wins, opp. riders 2nd and 3rd 3-3
Heat 2. No home riders turn up, opp. win heat 5-0 3-8
Heat 3 Home no.3 wins, opp. 2nd and 3rd (3-3) 6-11
Heat 4 Home no. 5 wins , " " " " 9-14
Heat 5 Home no. 3 wins ," " " " 12-17
Heat 6 Home no. 1 wins ....................... 15-20
Heat 7 Home no. 5 wins ....................... 18-23
Heat 8 No home riders opp. win heat 5-0 18-28
Heat 9 as the home side are behind by more than 8 points, their lone rider (no.3)
is nominated as the golden jokeĀ® and wins for a 6-3 heat advantage
24-31
Heat 10 Home no.1 wins (3-3) 27-34
Heat 11 Home no. 5 wins......................................... 30-37
Heat 12 Home no.3 wins...........................................33-40
Heat 13 In their first pairing together, no.1 + 5 score a terrific 5-1!!!!
38-41
Heat14 Using the rider replacement rule, the lowest ranked heat leader rides in the place of a second string. and wins. (3-3) 41-44
Heat 15 The home pair score a 5-1 46-45
Now that's just plain silliness, but may be useful when you've got 4 riders injured.