One of the criteria for the CAU designation is "Filing or threatening to file a frivolous lien or a frivolous criminal or civil action against an IRS employee or contractor or their immediate family," which would apply to a number of tax nuts.
One excerpt from the report:
One of the points made in the report is that the CAF is the system that IRS employees consult to identify taxpayer representatives, and the CAF does not include any PDT or CAU information.TIGTA wrote:As of August 29, 2013, the Employee Protection System listed 84 taxpayer representatives with a PDT or CAU indicator. Although this number is a small percentage of the 2.3 million representatives in the CAF [Centralized Authorization File], the safety of frontline employees, and others working in the same facilities, is at risk when these employees unknowingly meet with potentially dangerous taxpayer representatives. Moreover, the number of taxpayer representatives designated with a PDT or CAU indicator may increase after the IRS takes corrective action to address the weakness reported in our previous audit. In Calendar Years 2010 through 2012, IRS employees reported four incidents of physical assault by taxpayer representatives. The IRS agreed that even one assault is one too many.