Other mistake: Just after Bobby and Cindy get lost, there are shots showing Mike and Carol calling for them. A couple of minutes later the same shots are shown again, but this time they're flipped. (00:22:00)
Continuity mistake: At home, before leaving for the Grand Canyon, the trailer was much taller than the car, and looked more like a motor home. After that, it becomes a different vehicle more like a trailer, about the same height as the car. When the prosecutor steals the car, it's the tall version, and when they arrive at the Grand Canyon to look at the view, there's nothing attached to the car bumper. When they leave the Grand Canyon it's the shorter version, back to being a trailer.
Answer: The dangling bracelet was used for dramatic purposes - to keep the audience on edge.