I don't think anything is really required unless you are carrying concealed and have the burden of informing. I think it's just a standard line of questioning designed to elicit information voluntarily. Seems like a very smart move.
I got pulled over recently and the officer caught sight of the missing key cylinder from the ignition. Long story but the cylinder locked up and had to be drilled out and removed. I haven't been able to successfully rekey the replacement ignition yet and have been starting it with a screwdriver. The officer asked me if my name was Joe Johansen when he knew my name was really Joe Jones. I'm sure it was just a method that if I responded yes he knew something was fishy and I probably had stolen the car. No biggy. Just them doing thier job using methods that have provided positive results. Kind of like opening with Do you know why I stopped you. You admit guilt right off the bat it makes things much easier for them to prove their case. Just my .02. :)