But Judge Emma Smith said the evidence showed ''a degree of sophistication''.
Not only did the mother of two steal the couple's chequebook, she also took a piece of paper which bore Helen Miller's signature.
''It shows you were pretty alert,'' the judge said.
Mowat's subsequent actions also showed some savvy.
She travelled up and down the South Island, between Christchurch and Invercargill, visiting various branches of ANZ, where she would make cheques out to cash.
Over the course of five weeks, Mowat had swindled a total of $35,350 over 15 transactions.
She also enlisted the help of another, 38-year-old Kellyann Ngawini Pakinga.
Pakinga received $600 for cashing three cheques worth $6450.
She claimed she did not suspect anything nefarious about the endeavour but that was rejected by the court at her earlier sentencing.
Pakinga was sentenced to four months community detention, nine months supervision and ordered to pay $2000 reparation.
Mowat's crime spree continued.
On January 28, she went to another Momona farmhouse, stole a 20-litre fuel container and drove off.
Just hours later, police caught her, though it took little detective work.
Mowat was found asleep at the wheel of her car on State Highway 1 at Allanton.
Officers found 15g of cannabis in the vehicle. She was ''drowsy and unable to follow basic instructions''.
Analysis of Mowat's blood laid her drug-addiction issues bare: methamphetamine, methadone, methylphenidate and THC.
Leonard said much of the money defrauded from the Millers was spent on illicit substances.
Mowat, she told the court, had physical problems stemming from a serious back injury and severe mental-health issues.
Judge Smith said there was no way the defendant could pay back the stolen funds but fortunately, the bank had compensated the family of the victims.
Mowat was ordered to pay reparation of $1433 and banned from driving for six months.
The judge declined an Otago Daily Times application to photograph the victim, saying it might exacerbate her psychological troubles.
