BBM-The bolded part of your post really stood out to me. That's exactly how I would describe Casey but you worded it perfectly. As crazy as it sounds, it wouldn't surprise me if Casey walked right past George with a deceased Caylee crammed in the laundry bag (blanket on top to disguise the body) on her way to her car. If George dared to even ask where Caylee was Casey could have simply cursed him out and said you all are #%*$! crazy so I took her to the nanny's house last night and that's where I'm staying. I think George gave up a long time ago on trying to reel Casey in, particularly when he took the time to go to Sports Authority and talk to the manager in order to verify she wasn't working. Instead of George/Cindy sticking together and holding Casey's feet to the fire, Cindy chastised George for checking up on her. I think the motto in that house was never make Casey mad.
I'm not saying this happened, I'm just using it as an example because as Marina stated, never underestimate would Casey would boldly do. George even stated that Casey pushes everything to the limit then pushes it some more. We've seen her in action (stealing videos, jail videos) and words (talking to detectives, jail letters) and it's truly scary.
IMO