what the cops are doing is essentially the equivalent of going online and offering to sell an ounce of .9999 pure gold for $10. of course it's bullshit, but eventually they get someone dumb enough or desperate enough to turn up, hoping that maybe it's legit after all. and then, when the sucker turns up, they arrest them and charge them with theft for trying to buy an ounce of gold for $10. despite the fact that the gold never existed, and no transaction ever took place.
Australia