Quarantine "yellow jack" but this was also a name for yellow fever, which probably derives its common name from the flag, not the color of the victims (cholera ships also used a yellow flag). The plain yellow flag ("Quebec" or Q in international maritime signal flags) probably derives its letter symbol for its initial use in "quarantine", but this flag in modern times indicates the opposite—a ship that declares itself free of quarantinable disease, and requests boarding and routine port inspection. Australia has perhaps the world's strictest quarantine standards. Quarantine in northern Australia is important because of its proximity to South-east
Flag of Australia treated with respect and dignity it deserves as the nation's most important national symbol". The National Flag must always be flown in a position superior to that of any other flag or ensign when flown in Australia or on Australian territory, and it should always be flown aloft and free. The flag must be flown in all government buildings and displayed in polling stations when there is a national election or referendum. Private pleasure craft can fly either the Red Ensign or the Australian National Flag. The British Blue Ensign can be flown on an Australian owned ship instead of