Continuity mistake: Maggie pulls the ladder from the rear of the firetruck, but in previous shots the only ladder on the firetruck is hung on the passenger side.
Knots Untie - S6-E11
Continuity mistake: When the bus gets stuck in the mud, the team leaves the vehicle. However, their shoes/boots are already covered in mud despite having not left the bus yet. (00:17:50)
No Sanctuary - S5-E1
Continuity mistake: Near the end when Rick thanks Tyreese, the cabin door is open after Tyreese had closed it as the group walked up. In next shot it is closed again.
Too Far Gone - S4-E8
Continuity mistake: After The Governor shows up at the prison with his arsenal, Hershel and Michonne are taken out of the vehicles and placed kneeling on the grass side by side, about 1 arm's length apart from each other. But when Rick makes his way down to the fence to talk with The Governor, Hershel and Michonne are now about 4 arms' lengths away from each other. This goes back and forth for a few shots.
Continuity mistake: When the sodas are retrieved from the cool box there are 6 cans, but when the angle changes there are only 4.
Beside the Dying Fire - S2-E13
Continuity mistake: When the farm is overrun, the tires on Daryl's motorcycle are offroad tires. Later in the episode however, these tires change magically to smoother street tires. (00:15:35 - 00:28:40)
What Happened and What's Going On - S5-E9
Continuity mistake: Tyreese, Noah, Rick, Glenn and Michonne all go to see Noah's old base in search of his family. Tyreese gets bit, and they begin to run back to the car. Except for one tiny clip, Daryl is running alongside them, even though he was with the other half of the group. (00:33:15 - 00:33:40)
Chupacabra - S2-E5
Continuity mistake: Daryl ripped off his shirt to wrap around his wound, and was left in only his vest. Except, a shot later, he's seen wearing his shirt again, cutting off the walker's ears. (00:25:30)
Continuity mistake: The stinger is deployed and is seen. Camera changes into the car and the stinger has vanished from the road. (00:09:20)
Continuity mistake: When Jessie brings a basket of stuff to Rick the paper towels are on her right, then when Rick takes the basket they're on her left, and then in the next shot they're back on her right.
Pretty Much Dead Already - S2-E7
Continuity mistake: As Daryl and Shane argue near the start, Daryl's movements don't correspond with the changing shots: one moment he is standing in front of Carol, then he is standing by her, then he has moved closer to Rick - all within the same one-liners. As his argument with Shane grows, he again is standing by Carol, or closer, near Rick. At one point, a shot shows Daryl about to lounge at Shane, as Rick blocks him, but the very next shot shows him right next to Carol, who at that point would have been standing behind Rick. (00:10:00 - 00:11:00)
Continuity mistake: When helping the foreign family to fight off the walkers, Daryl pulls the zombie back into the car and slams its head in the boot door, covering his hands in blood in the process. However, for the rest of the scenes in the episode and in shots directly afterwards, his hands appear totally clean without him doing anything to clean them. (00:22:00)
Continuity mistake: The previous episode ended with Rick and his group reaching Woodburry and it was dark. This episode starts with Tyreese and his group reaching the prison in the daylight, and being rescued by Carl and brought back to their cell block. If you look at the windows it is still light out, they have no electricity so it can't be exterior lighting, yet in the scene before and after this, Rick and his group are at the Woodburry at nighttime.
Continuity mistake: When Eugene sees the walkers come out of the woods, the road is wet. The rest of the scene the road is dry.
When the Dead Come Knocking - S3-E7
Continuity mistake: The Governor takes off his gun belt while interrogating Maggie, and a few shots later has it on again in the same scene.
Continuity mistake: In the golf club Beth is wearing her new yellow t-shirt and white cardigan. Daryl hits walker blood all over her cardigan. In the next scene she takes the cardigan off and the t-shirt underneath (which was covered by the cardigan) has blood all over it. Back in the forest after this the shirt is clean again. (00:18:20 - 00:21:35)
Continuity mistake: Right at the end of this episode when there is another flashback to the prison, the baby is seen many times. Judith is asleep, then the camera angle changes and she is awake, it moves back to another angle and she is sleeping again. This is repeated several times.
Pretty Much Dead Already - S2-E7
Continuity mistake: After Carol tells Shane they are not leaving without finding Sophia, Daryl enters and reminds Shane about the doll he found down at the swamp earlier, and they start to argue. During this he crosses front to Carol's right. In the very next shot Daryl is suddenly shown standing in the same spot as prior, next to Carol. (00:10:00)
Continuity mistake: After they steal the car with the alarm blaring, there is a shot of the white van turning left down a road. It has just rained but the road is bone dry. A shot later there is water on the road.
Arrow on the Doorpost - S3-E13
Continuity mistake: In the final scene of the episode, Rick and Hershel are talking while looking out over the prison yard. Near the end of the conversation, Rick squarely faces Hershel and says "I'm hoping you could talk me out of it." The camera then changes to Hershel, and Rick is now immediately facing 90° to his left looking over the yard. When the camera changes back to Rick, he is now looking directly at Hershel.
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.