And you really think IRS goes after deceased nonfilers?

This is an example of the “it used to be, so it still is” fallacy. Here is an excerpt from a study of the IRS non-filer program:

“Each year, the IRS return delinquency process identifies individual taxpayers who may have a filing requirement but have not filed a tax return by the required due date. A portion of these identified individual taxpayers are contacted about an unfiled return. For various reasons, the number of contacts has decreased over time. Over the last five tax years (2010 through 2014), the IRS went from contacting over three million individual taxpayers for unfiled 2010 tax returns to just over one million for the 2014 tax return.”

OK, so those are old figures. What happened after 2014? This is from an official IRS Advisory Council report:

“From FY 2011 to FY 2014, the IRS collected $11 billion from the Automated Substitute for Return Program (ASFR) (a component of the IRS’s overall nonfiler strategy); however, during TIGTA’s 2017 audit, it was determined the program had been suspended due to resource issues. In an audit of the IRS’s
overall nonfiler strategy, TIGTA learned that, due to resource issues, the IRS decided not to pursue high-income taxpayers who had submitted applications for extension of time to file tax returns for Tax Year (TY) 2012 but did not file a tax return...”

The IRS has few secrets. They put online most of their instructions to employees. These are generally written so a GS-4 clerk can follow them. So why don’t tax practitioners read the same instructions so they know what IRS is doing? I really don’t know. But here is an example of what IRS clerks are told to do if someone says they don’t have to file because they had losses on that stock that was sold:

Internal Revenue Manual
5.19.2.6.4.6 (10-20-2016)
IMF - Determining Liability

Taxpayer states they had expenses (i.e. against business income) or a cost basis (i.e. against stock sales) that lowers their total income.

You can accept this information via the telephone or in correspondence (without a return) "ONLY" to compute the potential total tax liability and determine if there is a Refund Due or the tolerance amount was met for "Minimal" or "No" tax due per Policy Statement P-5-133.