At the last bank I was with, we satisfied the auditors by putting a procedure in place to conduct a cursory review of proof work prior to the work being picked up each day. That way a branch supervisor thumbed through a sampling of proof bundles before they were put into the locked proof bags picked up by the courier. They looked for, among other things, unapproved GL tickets and unvalidated cash in/cash out tickets. It obviously wouldn't catch everything, but it mitigated the risk to the point that the auditors could live with it.