WHAT'S GOING ON IN THE WALKING DEAD ?

In the Season 2 opener of The Walking Dead, our group of terrified zombie apocalypse survivors found themselves ambushed by a herd of walkers on a highway that looked like it was the scene of a demolition derby. With the meatbags closing in on them, Rick Grimes decided the best way to keep everyone alive was to forgo the weapons and get out of sight, so he ordered everyone to duck under cars, as the herd o' dead guys shuffled past, clueless to the fact that lunch was right at their decaying feet.

This raises a very interesting questions: "Wait, what?" In Season 1's "Guts," Rick and Glenn made a big deal out of covering themselves in zombie innards so the walkers wouldn't smell them. It worked, until a downpour of rain washed off the zombie intestine cologne. After that, Rick's plan became "shoot them in the head and run," because the zombies were starting to smell the human stink on them.

1. Why didn't the zombies sniff out the survivors hiding underneath the cars ?

2. What's up with all the dead people in cars ? Did something happen ? Did they get bored to death ? Why didn't the zombies eat them ? Why were they just... dead ? ... The cars are perfect, they didn't die in accidents.

AMC's Zombie Rules for The Walking Dead, as Tweeted before the Season 1 premiere:

Zombie Rule #1: Ability to run is based on the amount of time a zombie has been undead, and how much decay has set in.
Zombie Rule #2: Zombies decay but at a much slower rate than humans, and it's still possible to differentiate between young and old zombies.
Zombie Rule #3: Zombies are like lions: if they've eaten, you can walk by them without fear, but a pack of hungry zombies will attack you.
Zombie Rule #4: The quickest speed of any zombie is a shambling run. see Night of the Living Dead. NO sprinters exist.
Zombie Rule #5: Zombies are not dexterous. They cannot pick up or use any items more complex than a rock or a stick.
Zombie Rule #6: Zombies have poor eyesight but they do have a strong sense of smell.
Zombie Rule #7: Zombies cannot speak but can communicate by pack mentality. The herd tends to move together if they sight food.
Zombie Rule #8: There is no overt recognition of people or places, there is a sense of familiarity that can dictate where a zombie moves.
Zombie Rule #9: There's no known cause of the zombie mutation, but it's suspected to be a virus or infection.
Zombie Rule #10: Once you're bitten you'll die and reanimate as a walker. How long it takes is related to the nature your bite.