Moving at a rate of roughly 2.8 inches per year, the Australian plate is one of the fastest continental plates on the planet, requiring the country to updates its coordinates four times in 50 years. The last time Australia changed its coordinates was in 1994.
While a distance of five feet doesn't seem like a big deal, since your smartphone's GPS system is accurate to approximately 16 to 32 feet, the disparity could drastically affect autonomous systems. In the US, the average width of a highway lane is roughly 12 feet. If an autopilot system is off by five feet, it could result in the car being in another lane.
Since Australia moves at a rapid pace, the country's coordinates will be updated to its projected location by 2020, which leaves a few years until the country is really synced with GPS systems.