Under these circumstances, you have got to question, how long has the pet been with you. How long did the people leave the pet behind and which owner does the pet know more. I have a shelter cat that was abandoned by it's owner. I do not know the circumstances as to why it was left behind, but I would have a hard time if the original owners came back 1 year later wanting to pick up their pet.
And by the way, I did not see the whole thing. just enough to know that it involved the Huricane Katrina pets.