Treating Kickbacks as income is a neat way of taxing big players without incurring the risk of losses being claimed.
If the ATO adopts that approach, they will cover all bases for negating "claims for losses" by losing punters .
The ATO may look into taxing rebates however any income(or losses) from the actual betting have to be considered also. They are a function of one another.
Example - Player A gambles $1million dollars for the year and recieves a 5% rebate.
He loses $150,000 on his outlay and recieves $50,000 in kickbacks leaving a net loss of $100,000 for the year.
I seriously doubt that the ATO can tax him on the $50,000 rebate on top of the $100,00 he is already in the red.
He could argue that the rebate was simply a "discount".
Even though there is a chance the ATO could tax rebates, if the TABs wanted to do deals with big punters in future they could simply offer higher dividends than those declared.
So the 15% takeout declared dividend to the average punter might be 2.00 and the high volume punter would recieve 2.10.
In effect this would be the same as a rebate and something the ATO would have difficulty getting their hands on.