Online Compliance Intervention - later colloquially known as "robo-debt" - has started.

Mark, from Hobart's northern suburbs, was among those that were in for a shock. Living with mobility challenges and cognitive impairments, he worked nine hours per week for about 17 years, and diligently updated his income to Centrelink as part of his Disability Support Pension requirements.

But there was a problem. His employer gave compulsory leave during school holidays one week at a time, and his leave loading was paid in small increments over the year.

Centrelink's averaged income system found that this leave loading was not appearing in its averaged-out income system, and Mark was hit with a debt.

As the Northern Suburbs Action Group stated on his behalf, Mark "felt a great deal of anxiety at being made to feel as though he had committed a fraud". He paid the debt back, but when he tried to report his leave loading from then on to avoid future problems, Centrelink told him there was no need because it wouldn't affect his pension anyway, but he could try online.

There was no portal where he could do this online, however.

Throughout 2016 and 2017, story after story of Centrelink recipients caught in a similar web were highlighted, where seemingly arbitrary errors from years ago were being picked up.

I interviewed a man who received a $2558 debt for, apparently, working two jobs but only declaring his income for one. Centrelink added a few thousand supposedly missing from his income reporting from the mythical second job, decided he was in the wrong tax bracket, and issued a debt. An accountant found the problem though - when the aged care facility he worked for changed names, a separate company was created, and apparently he worked for both.

After dozens of calls, he finally had the debt waived. But he couldn't waive the $1200 bill to the accountant.

It was panic stations for social support organisations who were suddenly inundated with vulnerable people facing an entirely new source of trauma. They did all they could to lobby the government to change the system, to no avail.

So what was this all about, anyway?

The Australian Taxation Office had been providing income information to the Department of Human Services for 20 years to check employment income. What changed in late 2016, however, was the Turnbull government decided to automate it. Where a discrepancy was spotted between ATO and Centrelink, a letter was automatically generated. The algorithm estimated the income was earned evenly across the financial year, and the onus was on the Centrelink recipient to disprove the debt.

Why super-charge this process, though?

The answer: to fulfill the Coalition Government's election commitment called "Better Management of the Social Welfare System". It forecast that the new system would bring in $3.7 billion in "savings" over four years. There was a "budget emergency", remember?

For all the mental anguish, the scheme fell well short of its estimated savings anyway. It sought $300 million in debt recoveries from July to December, 2016, and of that, it recovered $24 million.

But the scheme continued, was planned to be expanded and then, when a class action was launched, the government started to back away. It turned out using averaged ATO data to calculate a debt was unlawful, according to the Federal Court.

It's a cautionary tale that bears repeating again and again until governments stop targeting the poorest to raise revenue.

The JobSeeker payment may have been a recent victory - brought on by incredibly specific circumstances - but it could just be short-term. Already, the "job snob" and "doll bludger" rhetoric has been flung around to start softening the public up for winding back the increased payment.

This language has happened before, it's been proven false, but it'll happen again.

What would be refreshing, though, is if we turned our attention to where the government is seriously missing out on revenue: tax dodging multi-national companies.

The website of Walkley Award winner and political scientist, Michael West, features an annual update of the worst offenders. Companies operating in Australia have hundreds of entities in tax havens like the Bahamas, British Virgin Islands and Cayman Islands and use shady financial practices to park their billions offshore. The top 10 had a combined four-year income of $172 billion in Australia, but paid a combined $9.3 million in taxes.

Who's the real problem? Mark from Hobart and his leave loading, or a multi-national company deliberately avoiding billions in tax in Australia? It's all about priorities.