What is the fraud perpetrated by Dolphus Raymond? (Chapters 18-21)?

Mr. Raymond pretends to be a drunk. The paperbag everyone believes contains a liquor bottle hides nothing but a bottle of Coca-Cola. When Scout asks why he would allow people to believe he is a drunk, he responds his odd behavior keeps people away.....thus, he doesn't have to explain himself or his relationship to the black community.

“Wh—oh yes, you mean why do I pretend? Well, it’s very simple,” he said. “Some folks don’t—like the way I live. Now I could say the hell with ‘em, I don’t care if they don’t like it. I do say I don’t care if they don’t like it, right enough— but I don’t say the hell with ’em, see?”

Dill and I said, “No sir.”

“I try to give ‘em a reason, you see. 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.”