She began training to join the force in 2008 but was not permitted to graduate the following year because of an allegation she had cheated on an assessment.
Despite what amounted to serious misconduct, police gave Yu another chance in 2010. She failed to pass one of the required assessments even though she sat the test six times, appealed the results three times, and underwent further retraining.
Unable to become a constable, she was offered - but did not accept - opportunities to apply for non-sworn positions with the police.
Yu argued that she had met the training requirements the first time around and been assessed then as capable of exercising the powers of a constable.
She also claimed she had been unfairly singled out by police college staff and made the butt of classmates' jokes.
In the early cheating investigations, the commissioner offered Yu a $19,000 settlement, covering lost wages, compensation and costs. She turned it down.
The IRA judgement said Yu was currently on unpaid leave while her future with the police was resolved.
She provided a sworn affidavit containing evidence of her present inability to pay more than a nominal contribution to the costs awarded against her. Yu had no income, owed her landlord more than $8000 in rent arrears and had a $24,000-plus debt for her own legal fees.
The authority pointed out that it cost just $75 for an employee to commence a personal grievance. As in Yu's case, that could lead to several days of meetings, as well as to liability for costs totalling 100 - and sometimes 1000 - times more than the modest filing fee.
"Parties acting responsibly need to keep a sense of proportion and have regard to the reality of the case and the risks involved in pursuing it," said the ERA.
Even if they succeeded, they might be worse off financially after taking account of legal representation.
"Where professional representation has been obtained, it should be by an advocate who has sufficient objectivity to be able to advise when a settlement should be accepted."
Yu was represented by a former inspector of the Rotorua CIB, John Dewar, who was jailed for 4-1/2 years in 2007 for attempting to obstruct or defeat the course of justice.
He has maintained his innocence over the charges, which related to the handling of historic sex allegations brought by Louise Nicholas against Bay of Plenty police officers.
Dewar was paroled in May 2009 after serving 19 months of his sentence. He now works as a employment relations consultant.
