Originally Posted by
number_6
No they are not! You have the rule backwards: for IATA airlines, the airline flying the last sector is responsible for lost or damaged baggage (even if they never received it from the preceding airlines).
The reason for this "multiple ticket no interlining" rule is strictly marketing: to get more revenue to alliance partners.
Correct, however the last airline also will charge back to Qantas a certain % of the amount depending on how and why the bag was missing. So while passengers deal with the last airline and they are responsible - that last airline will deal with the first (or the airline that caused the bag to go missing, or even shared between all the airlines involved) to get some or all of the money back.
Marketing - perhaps, but there is also cost saving involved too.