“We require all checks to be signed by two officers of the church”. 

Dual controls, or separation of the accounting duties, are an important brick in the wall of fraud protection.  Requiring dual signatures is often one of the ingredients in providing proper segregation of duties.  But, if this practice is not combined with a few other protective measures it will be no more effective as a lion with no fangs or claws.

True, the knowledge that all checks must be signed by two people will deter most people from taking a chance.  But, if this is the only control in place, it will not be enough to scare off a bold predator.

Let me set a scenario.  Imagine a bookkeeper who has been given the responsibilities to write checks, prepare the general ledger and reconcile the bank account.  If this individual has courage, handwriting skills, and lack of integrity the protection provided by dual signatures will be paper thin.  Ask yourself, how much more difficult would it be to forge two signatures than one?

My point?  Do not rely on dual signatures as your only wall of defense.  Dual signature requirements, standing alone, are no match for a check forger.