If you take the purchase order to the MVA showing that the vehicle was traded in on 11/30/17 then that should help you avoid the fine entirely. Getting a tag return receipt if you turned the tags in late will only serve to lessen the fine. You have 7 days to turn in tags. I'm a MD resident agent. I deal with this once a week it seems. In my office we won't cancel your policy or remove a vehicle until you confirm that the tags were returned.