This case is so bazaar the only thing I can think of is the fact that a ZG did live in Casey's neighborhood at one time. At the abandon house or close by. I don't have the links now but it was discussed in the abandon house thread. What if that ZG, which is said to have move - Cindy also claimed a ZG was being watched in P.R. was the ZG that at one time may of watched Caylee for Casey? Then, it just happen that a ZG went to Saw-Grass and bingo...Casey was desperate for an alibi for what she had done to Caylee and that particular ZG was at the wrong place at the wrong time. So, maybe Casey did mention to JG about the ZG that lived near her home way back. Just a thought.
Not sure if I did this correctly, but I also remember reading in another thread that Casey had a classmate in high school named Zenaida, different last name.