The flight route between Melbourne and Sydney used to be the second busiest in the world (not sure what is like now with the pandemic). There are a lot of peopl

The flight route between Melbourne and Sydney used to be the second busiest in the world (not sure what is like now with the pandemic). There are a lot of people moving between the states of NSW and Victoria. But during outbreaks in both cities, there were border closures which included not just airports but also roads on the land border which is about 1000 km long. This protected one city from cases from the other.