Bloodletting - S2-E2
Continuity mistake: When T-Dog is telling Dale that all he found was ibuprofen and cigarettes, he is holding his hand up and they are both looking at each other. In the next shot, suddenly his arm is down and they are both looking forward. (00:22:44)
Answer: Walkers are attracted to noise, they can tell who's dead and who isn't dead, in S1 when Rick and Glenn cover themselves in walkers' guts they're able to get far by walking through the herd of walkers because they smell like they're dead, but as soon as the guts get washed off by the rain the walkers immediately attack them, if you draw attention to yourself they will attack you which we've seen that many times throughout the series that it's not always successful. Whether you're covered in guts hiding under dead corpses or under a car.