Visible crew/equipment: When the camera pans out to an overhead shot as Annette and Sebastian hold hands in his car, a cameraman wearing a white shirt is visible, reflected in the car's windshield. (00:50:50)
Visible crew/equipment: When Cecile sits with her Diet Coke on the floor, Kathryn knocks on the door, and Cecile gets up to open it. If you look by the chandelier you can clearly see the whole boom mic come down into the shot. (00:50:55)
Visible crew/equipment: At the end of the film, when we see Annette driving the black car, as the camera pans up, you can see the camera crew in the reflection of the side of the car. (01:33:30)
Answer: Well, this is my own opinion, but I think that Annette and Katharine were just pretending not to know each other. Remember, Katharine doesn't know how much Annette knows and Annette knows what kind of deception Katharine is constantly pulling off. I also think that Annette uses the line "turning to God" to foreshadow (and maybe scare) Katharine. Naturally, it didn't work until the journal got out.