i think the no changing for teh cheap tickets is a bad move by qantas.

sure i don't fly alot but when i went from SYD-BNE with a group of 7 we turned up 4 hours early.

alot of flighs went out with plenty of room.

along came our evening flight.
It was oversold :-P

if they had let us go earlier it would not have been

now imagine if this happens about 200 times a day with a few seats involved.

it adds up