In my experience, accounts become dormant when the bank no longer has good contact information for the customer.
Where are you going to send the confirmation letter?
Goes back to the definition of "dormant" - to me, it's kind of silly to classify something as dormant when the account statements aren't being returned, but I guess some states aren't of the same opinion. It doesn't help, though, that a lot of people aren't clear on the differences between "inactive", "dormant", and "lost contact" - nor the legal issues surrounding them. I know I certainly wasn't the first time I was assigned to audit them.