If they had any sense at all their accountants would have been declaring all these other payments and benefits as assessable income. (the tax office is only interested in rorts that might effect other legal obligations like welfare entitlements, not what you might keep secret from your employer, or their commercial arrangements. So long as you pay the right amount of tax).
But we are talking about footy players here, not always the most sensible demographic. They'll live to regret it if the tax auditors move in and get hold of boats, and house renos, and 'charity' cash payments if they are not already declared....provisions allow for substantial penalties on top of the tax owing.