EMILY: So do I. We really ought to do something.
RORY: Yes, I agree.
LORELAI: Warning, warning.
EMILY: I’m glad to hear you say that Rory, because I thought of a wonderful way to cheer him up.
RORY: Cool, what?
LORELAI: Danger, Will Robinson, danger!
Lorelai is referencing the science-fiction television series Lost in Space (1965-1968). Inspired by the 1812 novel The Swiss Family Robinson, it followed the adventures of the Robinson family, pioneering space colonists, struggling to survive in the depths of space.
Will Robinson (played by Bill Mumy) was the youngest member of the family, a precocious nine-year-old who was a whizz with electronics and computers. He was accompanied by a robot (played by Bob May, voiced by Dick Tufeld), who was tasked with protecting Will. His catchphrases to alert Will when faced with potential hazards were, “Warning, warning”, and “Danger, Will Robinson, danger”.
The series received reasonable ratings and its catchphrases became part of popular culture, although never given much respect as a work of science-fiction. It was adapted into a film in 2004, and rebooted as a television series on Netflix (2018-2021).
The Annotated Gilmore Girls 