Norm and Christine Mackenzie have been providing their daughter, Sarah, with around-the-clock care since her birth 34 years ago, when a series of medical errors left her with cerebral palsy and other disabilities.
They sought and won a seven-figure compensation sum, which they've been managing carefully to ensure their daughter has the best quality of life possible.
But in the middle of last year, they began receiving letters from NSW Trustee and Guardian (TAG) that said under its new surety bond scheme they must pay an annual fee - $12,000 in their case - to protect the vulnerable from being "ripped off".
"They think we're going to steal from our daughter's estate, that we're going to defraud her, but we're her parents who have her best interests at heart," said Mr Mackenzie, of Sutherland shire.
"We care for her day in, day out; this surety bond is quite insulting."
Amid the outrage and resistance of 3500 private managers, including the Mackenzies, the NSW government is trying to establish whether it has the power to force them to obtain a surety bond.
But it has hit a hurdle, with the NSW Civil and Administrative Tribunal last week ruling - in a case instigated by a private manager - that it wouldn't refer TAG's questions of law about its powers to the Supreme Court.
Shadow attorney-general Paul Lynch said the refusal was noteworthy because it was a condemnation of the way the scheme has been imposed - as a blanket policy, not taking into account the individual risk of managers.
"The bond is being imposed on everybody, whether they've been managing an estate for 25 years with no problems at all, or just started," he said.
"They are parents, children, siblings of those who aren't able to manage their affairs, and suddenly they're not trusted to do something they've done successfully for so long."
A TAG spokesman said there many reasons why private managers could cause financial loss, including poor decision making and innocent mistakes. The bond would prevent lengthy civil action and ensure the managed person would be quickly reimbursed.
Since its launch, the scheme has raised questions about the government's intentions. Despite multiple inquiries, it hasn't released data about fraud and loss.
The initial letter states the bond "will be underwritten and managed" by advisory firm Willis Towers Watson, on behalf of Scottish company Aviva Insurance Limited, after it won a competitive tender.
The government has long kept silent about how many tenders were submitted, although TAG told Fairfax Media it received "four responses".
Mr Mackenzie said it appeared Aviva had the monopoly, because it was the only company mentioned in the letters. They were not given the option to find another provider.
Since Sarah's estate is worth more than $50,000, he has to take out and pay 0.4 per cent of its liquid assets - up to a maximum of $12,000.
"Families like ours work very hard in order to function almost normally and it takes very little to tip the scale and topple us towards a crisis," he said.
Mr Lynch said the rate of 0.4 per cent was double what was set by Aviva in England and Wales.
At a budget estimates hearing, it was revealed the average fee under the scheme was $1236. With 3500 private managers, the first year of revenue would be about $4.3 million.
Sofie Korac, a financial planner in Gordon, has managed her relative's estate for 24 years, regularly providing documents to TAG to ensure every cent is accounted for.
"They say it doesn't matter that I am a financial adviser and I have a 'best interest duty' that is now enshrined in law because they say I could get dementia or develop a gambling addiction," she said.
The NSW Law Society wrote to the Attorney-General last year saying it had concerns, including the policy rationale, mandatory application, cost and "unintended consequences" of the scheme.
"We are concerned that it is unfair to impose such a regime on financial administrators when there is no such equivalent scheme for attorneys, even though they are doing the same job," it said.
The new Attorney-General Mark Speakman has asked the Department of Justice to commission an external review of the scheme which will "examine the effectiveness of the scheme to date and its objectives".
"I am aware of the broader concerns the case has highlighted and I will seek advice on the NCAT decision when it is delivered," he said.
The TAG spokesman said: "It has never been mandatory to use Aviva specifically. Rather, TAG identified Aviva as a provider of an appropriate product at a reasonable price.
"[TAG] proposed that the CTS matter be referred to the Supreme Court because it considered the Supreme Court would provide the most authoritative answer."
Last year, the government made significant cuts to TAG, closing half its branches and filling the gap with online and phone services.