Answer:
The risk to the bank with the third party involvement could be considerably greater, particularly when the third party is outside your influence. There remains the potential for a check to be processed/deposited more than once and other forms of fraud (or, more charitably, customer error). You also don't have access to images of the deposited items to review for suspicious activity or for inter-account transfers that you might otherwise have blocked as part of an RDC agreement, as you would if you or your third party contractor were supplying the service.
First published on BankersOnline.com 9/13/10