This was a topic discussed when my institution moved to branch capture. Ultimately, it was determined that tellers running their own work (and correcting subsequent out of balance situations) did not present significant enough risk to justify mandatory segregation.
From my point of view, the scanning function is not serving as a control. Even when work was ran by an independent individual, they were not in a position to analyze appropriateness of transactions (not the right skill set, time constraints and limited data on tickets). As long as the transaction balanced, no attention is paid to validity. For example, a teller could include an unauthorized transaction in their proof work and as long as it balanced, the proof operator/scanner would have no need to look at it.
There are several other controls available to detect unauthorized account transactions, including independent reconciliation and review of internal accounts, customer review of statements, surprise cash counts and system reconciliation, as well as automated account analysis used to identify suspicious activity.
Last edited by Big Sky Banker; 08/21/09 07:18 PM.