Well, if we ever get the timestamp on that (I'm sure WalMart either has surveillance video or there was a purchase made with a timed receipt), we'll know for sure whether GA was telling the truth about seeing them leave around one p.m.
It also considerably narrows not only the time she had to do the deed, but almost eliminates any other person. KC would have had to wait until her dad left for work (between 2 and 3?), go back to the house - get ready for her "Blockbuster date" with AL, and have something happen to Caylee - all within an hour or two.
To me, that also lends more credence to premeditation and not an accident. If that "flurry of calls" was actually about getting ahold of family to report an accident and not otherwise as we have speculated, then she sure gave up quick and got her tail out of there well before CA might have come home.
Also, letting a toddler straggle into a huge store 10 feet behind you is not what most "Mothers of the Year" tend to do (unless they are cold and uncaring or extremely angry). The fact that KC strode in there without even holding her child's hand makes me think she was already thinking about how to get a "babysitter" for the evening.
I wonder what, if anything, she purchased while there.