You have a point, but what if it was staged to cover up not reporting it, as alleged by Casey?<quoted text>
No one STAGES an accident to LOOK LIKE a murder.
If this was a typical family, I would agree with you on this, but as George and Casey would not want Cindy to find out until they came up with a better way to tell her, I could understand it.
I think the story makes sense and I also think there's enough in evidence to back it up.
Besides, why would Casey keep it a secret if there was someone else involved? As you say, no one stages a crime scene to look like a murder if it was an accident, I say, no one risks the DP to cover up a killing.
Especially when it involved the death of her own child.
Unless she was taking the fall for someone she loved more than her own child, which I don't believe is possible for any mother to do.