Stupidity: Glenn's house is next-door (with not much space between) to Susan's. Christina's bedroom window is opposite Henry's bedroom window, but both 11-year-old classmates do not close their curtains (leaving space in the middle between the panels). Furthermore, Police Commissioner Glenn Sickleman - suspected of abusing Christina - does not bother to close Christina's curtains when he goes into her room to abuse her! This enables Henry to suspect (possibly KNOW) that Glenn is abusing Christina. (00:18:20 - 00:19:06)
Stupidity: While "sneaking" away from the school during the talent show, Susan squealed her tires pulling out of the parking spot (which wasn't in the best place for sneaking out). She speeds out of the lot and down the road, squealing her tires again making a sharp turn and cutting off a driver. These are ways of drawing attention to oneself and increasing the chances of being detected. (01:22:32)