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
What Is and What Should Never Be (Supernatural) its original broadcast, "What Is and What Should Never Be" was viewed by an estimated 3.11 million viewers, one of the lowest ratings for the season. Conversely, writer Raelle Tucker won the Constellation Award for "Best Overall 2007 Science Fiction Film or Television Script" for her work on the episode, and the episode garnered positive reviews from critics. Tina Charles of TV Guide "adored" the episode, and considered it to be Jensen Ackles' best performance of the series. She experienced an "emotional roller coaster the entire hour", finding Dean's monologue at his father's grave to be "crushing" but the lawnmower