I recently bought a project car. It is in great shape, I looked over every inch possible and really got a good deal.
Unfortunately, I was not aware of the fact that the owner of the car had not done the paperwork to register it when he bought it years ago. So this car was not in his name and had not been registered for many years. When it acquires a new owner who does do the proper paperwork, they are responsible for all the past registration fees. Now this is fine, if you know about it in the beginning. Looking back, if I had known about the near $600.00 in registration fees, I would have used that for leverage on reducing the price.
Make sure to investigate these things!