Dolphus Raymond is featured in chapter 20 of Harper Lee's To Kill a Mockingbird. We know from what Scout has witnessed, that he is basically known as the town's drunk. He is often seen drinking out of brown bag, just like drunkards tend to when they hide liquor. However, Scout discovers that what he is really drinking is pop (Coca Cola) and that he is only pretending to be a drunk. Here he explains his rationale.
Yet, the bag is clearly a symbol for privacy and independence. Obviously Dolphus is smart enough to know the dynamics of a small town. Although his actions may seem extreme, it sends a message about the amount of enmeshment that exists in Macon. In turn it shows how things such as gossip, lore, hatred, and myths also affect the town easily and super quickly. Imagine having to invent bad gossip about yourself in order to be left alone! Perhaps, however, he explains the meaning of the bag using his own words:
It helps folks if they can latch onto a reason. When I come to town, which is seldom, if I weave a little and drink out of this sack, folks can say Dolphus Raymond's in the clutches of whiskey--that's why he won't change his ways. He can't help himself, that's why he lives the way he does.