I concur, Lexington. No accident. This is the scenario I believe occurred, or something very close to it.
On June 15th, Caylee was the victim of a violent act at the hand of her mother, Casey, during a fit of rage brought on by the argument with Cindy. Cindy and Caylee had dinner at Cindy's mother's residence after the nursing home visit earlier that day. There was a discussion about the checks Casey stole from Shirley P. Cindy returned home and confronted Casey.
The argument escalated into a shouting match, and if LP is right, a physical altercation occurred between the two. I have no doubt, literally or figuratively, Cindy went right for the jugular. At this point, poor Caylee became the object of a tug of war. Or perhaps, Cindy threw them both out. At any rate, an enraged Casey and frightened little Caylee left the Anthony house. Caylee was crying. Casey screamed at her to stop, and when she wouldn't, the b**ch drove to an out of the way spot and struck her repeatedly, releasing all of the deep-seated anger she held toward Cindy. That poor baby died from blows meant for her grandmother. (I think Casey revealed that at the house on the night of July 15th before the police arrived, and that is what drove Cindy more deeply into denial.) What happened afterward is anyone's guess, but I do think she had assistance in dealing with the aftermath.
I came to this conclusion weeks ago, and nothing I've heard or read since has changed my mind. It's also possible that Caylee didn't die immediately. She might've suffered a concussion and fallen unconscious, and the stupid tot mom didn't realize how severely she'd injured her until later when she didn't wake up. That thought has bothered me for a long time, and when I heard the story about the nanny, the car accident, and the concussion, a chll ran up my spine.