Read the scenario and name the control principle that failed.
Two cashiers share one register drawer, and no one can say whose count was off when it doesn't balance.
The come down to a few habits: assign one task to one person, write everything down, insure what can be lost and the people who handle cash, and review the work independently.
is the one that shows up most often — splitting custody of an asset from the record of it, so no single person can take something and hide the evidence alone. It fails only through , which is exactly why it works as well as it does.