First appearance of the Greased Up Deaf Guy.
The title can also be based on the concept of "the thin blue line" which represents the brotherhood and close bond of fellow police officers.
When volunteering as a guide dog, Brian accompanies a blind man at the cinema to attend the film showing of The Blair Witch Project (1999).
Peter mentions being a security guard for George Harrison, and the cutaway shows him accidentally letting in the man who attacked Harrison and his wife with a knife in 1999. This episode aired four months before Harrison's death.
The title is based on the "The Thin Red Line" by James Jones