is to register your vehicle by VIN, rather than license plate. In practice, the teenagers they employ to check your vehicle don't know where to find a vehicle's VIN, don't do a great job of typing in the VIN, and would rather let you type in your email or read them your VIN in order to get you through the line as quickly as possible.
But that's a hassle for both sides. We did the VIN thing initially when we moved back to Utah from out of state (still had out of state plates for a short time), but it got old very quickly. Dealing with someone trying to type a 16 digit code on an iPad is as frustrating for me as for them.