Recently drove a 4,500 km trip in Australia, including near Mildura. We relied on two iPhones, one with Google Maps and one with Apple's newer version. For the most part, we relied on Google's maps and they never failed. Occasionally, we switched to iOS 6 and had a few different problems including roads simply not existing. After a while, we'd watch the iOS 6 directions just for a laugh.

Some of the stretches further East of Mildura run 100-200km without petrol stations and supplies. A number of the national parks in those areas are unmanned and irregularly visited, and there can be long periods even on sealed roads where you might not sight another car in an hour of driving. For one stretch (in and out of Mungo National Park), we stocked up on a lot of extra water as a precaution and notified family of our plans. Having an infant with us, I was very conscious of how quickly the temperature can rise once the air-con is off.

Can easily see how people might blindly follow maps/GPS and end up caught out. Especially when you're relying on cached phone maps data if your connection drops, as it does frequently out there.