And Aucklander Cathy Ellis has noticed how an obsolete GPS map could baffle people travelling along the motorway extension on the northwestern State Highway 16.
"If we are heading out west toward Kumeu, it doesn't recognise the motorway extension... it comes up that we are driving in a paddock," she said.
Mr Cappel suspected there were at least 100,000 units in the market with old maps.
"There is also the secondary issue where people buy their car nav unit, plug it into their car power socket and start driving, and then never or rarely connect it to the internet to update their maps."
He urged motorists to check information online at www.aamaps.co.nz.
Senior Constable Lox Kellas told an Otago Peninsula Community Board last week that tourists could be saved from getting in a "hell of a pickle" if GPS systems stopped sending them up paper roads.