30 Days Without an Accident - S4-E1
Continuity mistake: After Michonne gives Rick the shaver, he has his gloves in his right hand and the shaver in the left. As he walks up to the prison, he throws the shaver away on the ground. He continues up to where Carl is brushing the horse, still with his gloves in his right hand and left hand empty. He remains like this whilst talking to Carl, but as he pats the horse, then walks away, he has the shaver in his right hand and the gloves in his back right pocket. (00:11:44 - 00:12:14)
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.