Question: Who are Red Shirts?
Red Shirts was first introduced in Episode 1x11, All the Best Cowboys Have Daddy Issues.
Answer: In Episode 1x11, All the Best Cowboys Have Daddy Issues, Locke and Boone search through the jungle for Claire and Charlie. They have a red shirt and rip strips to tie on trees so that Boone can find his way back if something happens to Locke. They have this conversation:
"Ever watch Star Trek?" Boone asks."Nah, not really," Locke says.
"The crew guys that would go down to the planet with the main guys, the captain and the guy with the pointy ears, they always wore red shirts. And they always got killed."
Fans call the Lost extras, or background people, Red Shirts. The creators and writers will sometimes call the extras "Red Socks" as a joke.

