The 29-year-old woman and her 39-year-old partner, who both have name suppression to protect the identities of their children, appeared for sentencing in Auckland District Court today.
The couple had earlier pleaded guilty to one charge each of leaving a child under the age of 14 without adequate supervision.
Judge Grant Fraser granted the woman a discharge without conviction.
Her lawyer Richard Slade had asked for the discharge because the consequences of the offending would be out of proportion to the offence, APNZ reports.
The man was convicted and discharged. The children, aged between five months and eight years old, were freed by security staff and police during the incident in February.
The children were subsequently placed in Child, Youth and Family care. SkyCity said at the time there had been seven cases in the previous year of children being left in cars in SkyCity's Auckland car parks.