Some states have pretty strange rules - For example, MA does not recognize NY's temporary tags. If you are a MA resident & pull a trailer or drive a vehicle with NY temporary tags, even if you are just driving through MA, you can be ticketed for having/driving an unregistered vehicle: Quote from NY DMV "Important information for Massachusetts residents: Massachusetts (MA) does not recognize the NYS in-transit permit. According to the MA Registry of Motor Vehicles, you can receive a ticket for no registration
if you use an NYS in-transit permit in MA. This also makes the insurance on the vehicle not valid. MA authorities can impound the vehicle for no valid insurance. For more information, contact the MA Registry of Motor Vehicles ."
On the other hand, they let me register my trailer (with paperwork from the manufacturer in Canada) while it was 3000 miles away. Probably needed the $...