As much as I want to believe this was a tragic mistake... too many things are still not adding up. Even going into the car at lunch, wouldn't seeing the car seat jog the memory to think "oh crap, I forgot to take him to daycare!!!"??? And while the body may or may not have had an odor, if the child died from heatstroke and had that type of suffering, chances are he lost control of his bladder and bowels... but even if somehow he hadn't, we now know that he had just eaten a few hours before Ross went to the vehicle at lunch, and by that time would have likely had a messy diaper, that had been stewing in the heat. I just can't buy that the smell of a heated dirty diaper would not have alerted him in some way.
And the "maybe he was so confused by doing something outside his normal routine" (in a 3-5 minute span of time). IT people LIVE outside of routine. Nobody can convince me that this man forgot the child he had just had breakfast with mere MINUTES before, no matter if chick fil a was part of his "routine" or not. It's not as if he had been driving for an hour with a sleeping child and it slipped his mind.
As an aside, for anyone that has not seen the PSA on leaving children in cars, it's worth watching and helping to spread awareness that leaving them even for 15 minutes can severely damage or kill them. You can find it on YouTube titled "One Decision (Child Safety Film - Vehicular Heatstroke)"