ATO using facebook data to check your return...

I total agree that in this very specific case it was public data. What concerns me though is that ATO has been investing in its data mining and analysis capabilities.

They've also been putting requests into some businesses and schools as to the account details that services and school fees are paid from.

Facebook will give up your data at the drop of a hat;

V. How do we respond to legal requests or prevent harm?

We may access, preserve and share your information in response to a legal request (like a search warrant, court order or subpoena) if we have a good faith belief that the law requires us to do so. This may include responding to legal requests from jurisdictions outside of the United States where we have a good faith belief that the response is required by law in that jurisdiction, affects users in that jurisdiction, and is consistent with internationally recognized standards. We may also access, preserve and share information when we have a good faith belief it is necessary to: detect, prevent and address fraud and other illegal activity; to protect ourselves, you and others, including as part of investigations; or to prevent death or imminent bodily harm. For example, we may provide information to third-party partners about the reliability of your account to prevent fraud and abuse on and off of our Services. Information we receive about you, including financial transaction data related to purchases made with Facebook, may be accessed, processed and retained for an extended period of time when it is the subject of a legal request or obligation, governmental investigation, or investigations concerning possible violations of our terms or policies, or otherwise to prevent harm. We also may retain information from accounts disabled for violations of our terms for at least a year to prevent repeat abuse or other violations of our terms.

Maybe I'm being overly sensitive to this... but it doesn't seem too far of a stretch for them to acquire the facebook data under the idea of fraud prevention and use it, like the big marketing firms do, to build profiles of people.

I'm certainly not pro tax or big government. We need to fight this through a war of ideas not people playing accounting tricks. This simply gives the government an excuse to grow bigger and have more power.