"It's enjoyable to talk to people from other countries and they feel a hell of a lot better leaving their vehicles when we're there.
"They always give us a 'thank you' when they come back to their vehicle and see it's still there."
Mr Wagner has seen suspicious cars approach carparks, their occupants taking a good look at the volunteers watching over the cars before turning around without stopping - a sign the volunteers are effective, he said.
Meanwhile, a group of residents from the Tutukaka Coast community, who wish to remain anonymous, donated time and money to install a security camera at the Whale Bay carpark.
They said they were sick of holidaymakers leaving the beautiful beach upset and angry after their cars had been broken into in the carpark.
Summer Safe is now on the hunt for more volunteers to pitch in to watch over a carpark.