Answer:
One person having both keys to any secured area defeats the purpose of having two keys or dual control. I would not recommend that the teller leave with the keys and leave the bank with no way to access the "mallet" (I am not familiar with the term, but get the idea) when this may be needed to balance or for a replacement teller to work. If the bank does have any duplicate keys, these should be under dual control. That assures the teller that no one person could have accessed their area.
First published on BankersOnline.com 12/08/08