However, Winter testified that she had said that "I do not know any lawyers", and that she did not understand her right to a lawyer or that a list of lawyers could be made available.
Crown counsel Brenna McKenzie and Cameron Stuart prosecuted on behalf of the police.
Under questioning from Stuart, Winter agreed that she was over the limit after drinking three glasses of wine, that Robertshaw had read her rights out from a form, and that she had signed that form three times in different places.
Questioned about her fluency in English, Winter said that she studied English at school and had since become fluent but that "I don't understand everything that is said to me".
She said she did not recall being offered a list of lawyers.
The court heard she had never been in trouble in Germany, and the night she was charged was her first encounter with police since arriving in New Zealand several months earlier.
She agreed with Stuart that she would not sign a contract that she did not understand but "if I'm asked by a police officer to sign something I would".
Judge Kevin Phillips found that Winter had been appropriately advised of her rights and found her guilty.
He remanded Winter on bail until March 11 after Lafferty advised that he would seek a discharge without conviction.