This is what I figured the case to be. Where Casey gets a free ride with Cindy, George didn't always play Casey's game without prodding back a bit about responsibility. Something that, like the truth, is a total stranger to Casey. Casey would know she couldn't argue much with her dad - he was paying her bills - so she just dreaded dealing with him.
I think this is evident when George insisted on getting that "tool" out of Casey's car trunk when she stopped by once after Caylee's disappearance. George might not have suspected anything about Caylee at the time, but he wanted to see if it was Casey who had stolen his gas cans. She did, and he knew it.