Not every document you are given forms part of the contract for your flight.
Some documents are issued for information only and do not form part of the contract and nothing in them is enforceable - at least in contract law.
They may be enforceable in consumer law but, as others have pointed out, this would only apply to representations made BEFORE entry into the contract.
In any event, if anyone is seeking to rely on an error in a contract document, as a general rule, never bring it to the attention of the other party UNTIL the moment you seek to rely on it.
If they had turned up at the checkin counter with the baggage, with no time to take it back home, they might have got away with it.
Contacting Qantas merely provided them with an opportunity to correct their mistake and clarify the allowance.
From a legal perspective it is difficult to see how there could be any remedy available in this situation.
I'd take the 10,000 points and use them for an upgrade on a domestic flight.
That's worth a lot more than a Qantas branded mug.
