Michelle QLD has bought in laws that mean (when they come into effect) no one will be able to advertise unless they have a breeder number. That means no advertising on Gumtree, Trading Post, classifieds etc it will be enforced. That doesn't stop them from advertising on their facebook page or doing up flyers and dropping them off. Mind you the cost of the breeder number app is only around $400 for 3 years or something. It will in no way stop people from BYBing (or stop BYBers from getting a number). We need laws that makes BYBing illegal not just advertising BYB litters.
ETA - Here is a link to the laws on the GC http://www.awlqld.com.au/making-change.html