Questions about the film
First off really enjoyed the film. It definitely doesn't need some deeper non-obvious meaning to work. But there were a few strange scenes that must have had some purpose that I can't put my finger on.
(1) Toward the climax of the film, we see a flashback to the previous summer in which Catherine, Ginny, and James are about to go for a swim, but Catherine refuses. Just an odd scene. Why was this particular flashback included near the film's climax, or even in the film at all? Also of note, earlier, when Rich, Ginny, and Catherine are out on a canoe, Catherine is apprehensive about having her life preserver on correctly before the canoe departs. Neither Ginny nor Rich are wearing a life jacket. I assume this implies that Catherine is afraid of water/can't swim. We also see her staring out over the water at various points in the film.
(2) There is a scene just prior to or just after the party scene in which Catherine is standing outside the lake house, it is night out, and in the distance we see a boat pass by with it's lights on. It appears to be performing some kind of search. Catherine looks pleased. Presumably the Director had a specific reason to include this scene, but I don't know how it fits.
(3) The jogger scene and the party scene. Some have suggested that this is all a dream/hallucination. So who knows. Both the jogger and the party-goer mistake Catherine for the owner of the house: the jogger claiming to have seen her at a previous party, and the party-goer claiming to have seen her on TV during the investigation/prosecution of Ginny's family. Presumably she's being mistaken for Ginny. Maybe it's related to the theme of role reversal we see throughout the film? Or is there something else to it? She seems annoyed when the party-goer asks her if her Father and Ginny's Father were friends. Maybe she was offended that the party-goer would suggest her Father would be friends with Ginny's Father (a possible criminal)?
(4) The scene earlier in the film where the landscaper gives Catherine that cryptic warning about staying at the lake house. He hinted that people might come looking for pay back after being defrauded. The reason for this scene may be self explanatory: to introduce the shady background of Ginny's family. Presumably this was the "bad thing" that happened to Ginny 3 years prior that Catherine alluded to. It seemed the scene would foreshadow something later in the film, but nothing came of it.
I'm not trying to micro-analyze the film. Just curious if any more astute cinephiles on here have any theories.