If I am not mistaken, Islamabad plates can be retained by the first owner once he sells the car. Suppose you have the number IDA 1, so once you sell the car you can retain this number and install it on the new car. Your old car will have to be re-registered by the new owner. Of course, the resale will be affected.
I am sure the Punjab government's scheme will be successful if they can curb number plate theft. I use copy plates on my own car for fear that the original plates might get stolen. Plus the metal was rusting badly even when the plates were safe in my cupboard so I preferred not to expose them to the environment. We still have a very very long way to become a car conscious society.