No wonder Jean and Sophie are on le nez. Of course it could. Melbourne is up to its third chin in poets of haute cuisine. Some of them may well have been tempted to offer Wallace Lake oysters and serve instead dreck from polluted rocks near Sydney. Some may have specified Toolangi potatoes when all they've mashed is sebagos.
All fish are equal, but salmon more equal than others.
However, I don't think such frauds are perpetrated very often. This is Melbourne, and we Melburnians aren't mugs. There are some things with which we will not put up, and culinary fraud is one of them. I admit to eating more often than most, but I've seen little to arouse suspicion. It indicates misanthropy beyond anything known here.