Sorry I should have clarified, the ABN will give you more credibility as a sole trader, so set up a business.
There's no way the tax office will come after you as a pro punter anyway.
Can you imagine the GST claims from all losing punters coming in?
Software, computers, adsl lines, foxtel, formguides, petrol, car repairs.
It would be a rort and they know it.
Plus if you work fulltime or part time as well, then you;d pay no tax at all as a losing punter. So the ATO would have to give you back all tax you've paid!!!
A winning punter of course could give net profit after commission, and other deductions, but part of your business could involve overseas travel at your expense including hotel accomodation.
It's a deep deep hole they have no answer to, plus it used and still could be a cash only business
You're only really in trouble if you rent an office and hire staff (apart from your spouse). Many large punters have been asked and the ruling always comes down, not a taxable business.