Those proponents of this argument contend that section 6020(b) obligates the IRS to prepare and sign under penalties of perjury a federal tax return for a person who does not file a return. Thus, those who subscribe to this contention claim that they are not required to file a return for themselves.
The Law: Section 6020(b) merely provides the IRS with a mechanism for determining the tax liability of a taxpayer who has failed to file a return.
Section 6020(b) does not require the IRS to prepare or sign under penalties of perjury tax returns for persons who do not file and it does not excuse the taxpayer from civil penalties or criminal liability for failure to file.
Among the relevant cases United States v. Barnett, 945 F.2d 1296, 1300 (5th Cir. 1991) can be cited- where defense counsel in prosecution for willful failure to file individual federal
income tax returns raised inference that the IRS actually had some
statutory duty to file returns for delinquent taxpayers, court properly
instructed jury that IRS has no such duty. **
** Extracted from http://www.irs.gov/taxpros/article/0,,id=159932,00.html#_Toc153765510