Tiger like most LCCs is a point to point carrier, which means they do not provide connections onto their network or onto any other airline. Looking at their website, they sell ONLY Singapore out of Darwin. If their flight arrives too late to connect onto another flight you have booked, you will have a tense time finding out whether they are going to be nice about it.
It is up to the passenger to know what sort of visa is required by someone with the passport being used.
The Airline program about Easyjet shows their staff trying to repair mistakes made by passengers - some of those mistakes are beyond belief.