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) creepy look to it". He was pleased to see Smith and Palicki return, and found the character of Carmen to be "a nice addition to the family". Don Williams of BuddyTV agreed, and ranked the episode third in his list of the best episodes of the first three seasons. Deeming it the best standalone episode, he noted that it "can be embraced by anyone who enjoys clever writing, great acting, or a shirtless Jensen Ackles". General Specific Notes What Is and What Should Never Be (Supernatural) "What Is and What Should Never Be" is the twentieth episode of the paranormal