We know that the zombies can smell humans.
We have also seen characters use alcohol to try and mask their scent.
But what if the alcohol is actually repelling the zombies?

1. When Saul was trapped in the hybrid, the zombies left after the bottle of whiskey broke on his back.
2. Riley and Angel broke wine bottles to cover their trail and hid in the walk-in refrigerator.
3. When asked why zombies did not swarm in when the Maller's first laid seige to the Tower, Kc said the Maller's have a way to dispatch whatever Z's were in the area quietly. Could the Mallers be using alcohol to acheive this?
4. While running away from zombies, Victor broke cologne bottles as a defense, despite the Colony not knowing about the zombies sense of smell. (I believe most colognes/perfumes are alcohol based)
5. In chapter 25, Riley is passed out in a field from drinking. Was the strong scent of alcohol on her enough to protect her from the encroaching zombies?

The evidence is mostly circumstantial, but I've been jostling this theory around in my head a while and thought I'd put it out there to find out what others might think.