I've done about 40 miles with the ---- flashing.
There seems to be about 10 litres left in the tank when it starts flashing by my estimate and I do 7.6 km/l so 76km/47mile leeway.
This sounds reasonable for Nissan to build in a 50-mile safety buffer beceause this car was built for the US market. Having driven around Nevada/Arizona/Utah a few years back, there are a lot of areas where a petrol station 50 miles away would be the norm.