Good question.I'll address Alicia first...she OBVIOUSLY doesn't understand it otherwise she would have made the appropriate move with Christina this past episode.
If the F3 truly is Kim, Chelsea, and Sabrina, not only would Kat not undetstand that...I wouldn't either.
Hard to believe Kim and Chelsea would want someone like Sabrina as a finalist who, I think, would be able to handle the Q&A and come off much better than a bubbleheaded Kat. Kat's performance would be comical for the viewers but wouldn't win any votes.