According to the authority finding, problems began when the children, now aged 5 to 13, started complaining "about the way Ms Fisher drove and alleging she swore in their presence".
Ms Fisher denied swearing. At a later family meeting, Ms O'Brien told the nanny it was "scary to speed".
The final straw for Ms O'Brien came on June 22, 2011, when Ms Fisher was caring for the five children and three others while the O'Briens went to dinner with friends.
"There was some discord which led to both Ms Fisher and one of the children telephoning Ms O'Brien during dinner expressing their discontent," said the finding.
The next morning, Ms O'Brien texted Ms Fisher saying the employment arrangement could not continue because it was too hard.
Mr Loftus found Ms Fisher was unfairly dismissed because her employer didn't try to find out what happened or explain letting her go.
He ordered Ms O'Brien to pay Ms Fisher $4000 as compensation for humiliation and hurt feelings and $1779 in lost wages.
Ms O'Brien said she would not hire another nanny without a written agreement.