TOSS must enforce that successful/unsuccessful uses of the "useradd" command generate an audit record.
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.
Audit records can be generated from various components within the information system (e.g., module or policy filter).
The "useradd" command modifies the system account files to reflect the changes that are specified on the command line.
How this relates to the STIG checklist: STIG vs SCAP benchmark.