In the old days...
...when they still had vagrancy laws, every AP I knew had a "business" which (a) kept him immune from "no visible means of support (i.e., vagrancy);" and (b) a plausable alternative source of income for tax purposes.
Typically, he'd pay some small businessman, often a used car lot, a small premium to get a regular "paycheck." The businessman would pocket, say $250, tax free and cut the AP a paycheck for $200, less withholding. The $200 plus payroll taxes were deductable for the business, thus lowering his tax bill. IOW, the businessman profited on both incoming and outgoing money -- pretty sweet deal for him.
Yes, the AP would pay taxes on the $200/week -- but that was the whole point, if you think about it -- NOT paying taxes on his real gambling income. Everybody wins, except the IRS.