I realize it's a joke, but legally the government outside the IRS isn't allowed to look at your tax returns. If you are a pimp or a drug dealer, you must file taxes with your correct occupation, however these taxes are not admissible as evidence against you, and law enforcement doesn't have access to it to point you out as a drug dealer.
I don't buy this.
Title 26, United States Code, Section 6103 states:
(i) Disclosure to Federal officers or employees for administration of Federal laws not relating to tax administration
(1) Disclosure of returns and return information for use in criminal investigations
(A) In general
Except as provided in paragraph (6), any return or return information with respect to any specified taxable period or periods shall, pursuant to and upon the grant of an ex parte order by a Federal district court judge or magistrate judge under subparagraph (B), be open (but only to the extent necessary as provided in such order) to inspection by, or disclosure to, officers and employees of any Federal agency who are personally and directly engaged in—
(i) preparation for any judicial or administrative proceeding pertaining to the enforcement of a specifically designated Federal criminal statute (not involving tax administration) to which the United States or such agency is or may be a party,
(ii) any investigation which may result in such a proceeding, or
(iii) any Federal grand jury proceeding pertaining to enforcement of such a criminal statute to which the United States or such agency is or may be a party,
solely for the use of such officers and employees in such preparation, investigation, or grand jury proceeding.
(4) Use of certain disclosed returns and return information in judicial or administrative proceedings
(A) Returns and taxpayer return information
Except as provided in subparagraph (C), any return or taxpayer return information obtained under paragraph (1) or (7)(C) may be disclosed in any judicial or administrative proceeding pertaining to enforcement of a specifically designated Federal criminal statute or related civil forfeiture (not involving tax administration) to which the United States or a Federal agency is a party—
(i) if the court finds that such return or taxpayer return information is probative of a matter in issue relevant in establishing the commission of a crime or the guilt or liability of a party, or
(ii) to the extent required by order of the court pursuant to section 3500 of title 18, United States Code, or rule 16 of the Federal Rules of Criminal Procedure.