Obtained from travel.com.au

TRAVEL M U S T BE TO/FROM OR VIA ADJACENT
CONTINENTS A N D MUST BE IN A CONTINOUS FORWARD
DIRECTION BEWTEEN SOUTH WEST PACIFIC-ASIA-EUROPE-
AMERICAS-SOUTH WEST PACIFIC (TC3-TC2-TC1).
BACKTRACKING WITHIN A CONTINENT IS PERMITTED
- EXCEPT AS SPECIFIED IN ROUTINGS.
* ITINERARIES WHICH INCLUDE BOTH EUROPE AND THE
SOUTH WEST PACIFIC MUST BE A MINIMUM OF FOUR
CONTINENTS. NOTE: TRAVEL ON A SINGLE FLIGHT
NUMBER BETWEEN AUSTRALIA AND EUROPE MUST BE
CONSIDERED AS TRAVELLING BETWEEN THE CONTINENTS
OF SOUTHWEST PACIFIC-TO ASIA-TO EUROPE
(I.E. THROUGH THREE CONTINENTS).


ONLY ONE INTERCONTINENTAL DEPARTURE AND ONE
INTERCONTINENTAL ARRIVAL IS PERMITTED IN EACH
CONTINENT - EXCEPT AS FOLLOWS:
1)TWO PERMITTED IN NORTH AMERICA WHEN ONE IS A
TRANSFER WITHOUT STOPOVER. NOTE: TRAVEL BETWEEN
USA AND CANADA IS NOT CONSIDERED INTERNATIONAL;
2)TWO PERMITTED IN ASIA WHEN ONE IS A TRANSFER
WITHOUT STOPOVER OR ON DIRECT SINGLE PLANE
SERVICES BETWEEN THE SOUTH WEST PACIFIC AND
EUROPE;


Therefore the reason why they put rule number 2 is for people who do:

AUS-ASIA-EUR-USA-ASIA-AUS


Really confusing, has anyone done this routing before?