@Jhford I can not prove what doesn't exist; I can only prove what does exist.
<<why is it the taxpayer's obligation to do the IRS' work for it by reporting it>>
then by that logic, why file the original return either?
the obligation is because failing to do so under a voluntary compliance system would be tax evasion.
From the IRS website:
The U.S. income tax system is based on the idea of voluntary compliance; it is the taxpayer's responsibility to report all income. Tax evasion is illegal. Some people try to evade paying taxes by failing to report all or some of their income.
https://apps.irs.gov/app/understandingTaxes/student/whys_thm01_les03.jsp
