Mrs Chilton said her husband was driving at 100km/h at the time and they estimated that the vehicle in question was travelling a bit faster than them.
The car was a rental owned by NZ Rent A Car. Owner Marty Oetgen told the Herald that the men returned the vehicle just after 1.30pm today.
The police were waiting when they arrived.
"Following the coverage in the media (of the incident) we had a call from the Milford Sounds Lodge," said Mr Oetgen.
"They were also looking for them. They had allegedly stolen some items from the lodge. We passed that information on to the police and they were waiting for them when they returned the vehicle."
When confronted about their filthy behaviour in the rental car the men initially denied it.
"They denied everything, but once the police showed them the photos they said 'yes, that was us'," said Mr Oetgen.
He charged the men a cleaning fee of $250 to "decontaminate" the vehicle. It was not clear if any urine was present but Mr Oetgen was not prepared to take the risk.
"They didn't want to pay it but I think they realised that it was the only way things were going to move forward. And having two police officers standing behind them, they probably decided it was a good idea to just pay," he said.
"We don't want to put out a car which has potential contamination."
Mr Oetgen said the men left with police. They had a few mates with them when they returned the car.
"They are just young idiots. They're not hardened criminals or anything silly like that," he said.
"They're just stupid and they made some bad choices. They put themselves at risk and they put others at risk. I don't imagine they will want to come back to New Zealand in a hurry after this."
One of the men, Florian Birolleau, spoke briefly to Fairfax outside the rental car company's office.
He said it was the first time any of the men had urinated from a car window.
"We were just wondering if we could pee by the window. It was really difficult at the beginning.... I was a bit blocked by the wind," he said.
He said his mate "peed a bit inside" the car and Mr Birolleau urinated "a bit" on his shorts.
Another passenger Alexandre, who did not give his surname, said the group did not want to stop to use a toilet as they were running late. They were en route to the Milford Sound when the incident was caught on camera.
They said the first time they knew of their photo being taken in the act was when they pulled up to drop off the rental car and were confronted by media and the police.
• Motorists who witness dangerous behaviour by road users can contact either *555 or in an emergency, 111.
