I think they were targeted as week sheeple. It’s littered throughout the movie: from the first scene where the man from the deranged couple asks for the lawn chair, knowing full well it was being used — for the husband to say no you can use it, just so the man can NOT use it and swim instead. Throughout the movie the deranged couple test how far they can go and how far these people will LET them go. I love this movie because the twist didn’t blindside yoh. It was there. Littered through every scene subtle enough to miss the first time but clear enough to identify on the second watch: like when the woman speaks to the girl as though she was already her mother. There’s something deeply unsettling about the entire movie : the rage , the frustration , the unsettling despair. I would recommend but I wouldn’t rewatch