Income from undocumented worker

Your client has a valid deduction that he is not using, so I'm not sure if I would be comfortable with signing that return because the perjury statement says that to the best of your knowledge the return is "true, correct, and complete".  I could be wrong, but intentionally omitting a valid deduction doesn't seem to be a "complete" tax return.

In prior years, I would have definitely told the client they are an idiot and to take the deduction.  With all of the stuff that has been happening this year in regards to undocumented aliens ... I'm not sure how I would respond to the client.

When all else fails, read the Internal Revenue Code.

"Section 162(c)(2)Other illegal payments

No deduction shall be allowed under subsection (a) for any payment (other than a payment described in paragraph (1)) made, directly or indirectly, to any person, if the payment constitutes an illegal bribe, illegal kickback, or other illegal payment under any law of the United States, or under any law of a State (but only if such State law is generally enforced), which subjects the payor to a criminal penalty or the loss of license or privilege to engage in a trade or business."