It should be pounds responsibility to make sure the dog isn't wanted.
The suggestion that the pound has a responsibility to ascertain if a dog is wanted is laughable. How many millions of taxpayer money should be spent on a federal animal detective force to track down the legal owners of every stray animal? Should the pound have tracked down Mr. Fry in stir and sent a counselor to discuss his future intentions?
If he wanted the dog he would have called a kennel and paid to have his dog taken care of while he was away. That's what a normal dog owner who loved his dog would do.