A top Waiheke Island vineyard says Auckland Council noise control officers committed such basic failures when gathering evidence that a noise prosecution is doomed to fail.
But the council says there is ample evidence to convict Cable Bay Wine Ltd of the Resource Management Act breach, despite claims chirping crickets were responsible for the racket.
The wine company and duty manager Matteo Cozzolino appeared today in Auckland District Court to defend one charge laid under the RMA.
The council alleges "bass-dominant" noise from a function and live band breached the allowable 35-decibel limit at a neighbour's boundary on a summer's night in 2018.
If convicted Cozzolino could be fined up to $300,000 or jailed for up to two years, while the company - owned by Loukas Petrou - could be fined up to $600,000.
The vineyard's lawyer, Karenza de Silva, told the court failures by the council cast doubt on the reliability of evidence.
She cited staff accidentally deleting electronic data files from a noise monitoring terminal (NMT), and senior compliance officer Jacob Faafua failing to take notes of his site visit till recording them in an email 20 hours later.
"They let themselves down on the most basic things - losing the measurement file and not doing contemporaneous notes. These are basic things and they are fundamental," de Silva said.
"There's sufficient uncertainty that the prosecution can't prove this beyond reasonable doubt."
An expert acoustic consultant called by the defence, Rhys Hegley, told the court there was evidence of "residual" background noise on the night, including from chirping crickets.
But the loss of files meant he was unable to independently verify or quantify the contribution of cricket noise to the overall decibel reading.
"How confident can we be that the NMT gives exact level of crickets at Mr Faafua's location? That's where I struggle."
Council lawyer Stephen Quinn told Hegley there was no disagreement whether there was cricket noise on the night.
"There's only a question of how loud they were."
Hegley ruled out cicadas - "I've never heard of cicadas at nighttime".
Cricket noise was "insidious" and could be "quite loud". And despite the specific frequency of crickets, their chirping was often filtered out by the human ear, he told the court.
"When you were last at a barbecue no one talks about the crickets.
"The variability in cricket noise over a site can be quite large. Mr Faafua didn't quantify cricket noise. He wasn't focusing on the crickets, he was focusing on Cable Bay."
The court heard that an "adjustment" of 5 decibels was made to allow for background cricket noise, which still put the Cable Bay reading well over the allowable noise limit.
Quinn said while the loss of data files was "inconvenient" for the defence, it did not torpedo the prosecution case.
He added that Faafua's uncontested evidence was that there was no wind on the night in question and only a "slight" chirping noise emanating from crickets.
Judge David Kirkpatrick reserved his decision.