I know of the best reason that a rescued Greyhound was returned.
These teachers I knew were in their late 40's and childless. But their kids were their little white, poofy haired Pomeranians. These were their everything, just bouncy, spoiled, little dogs. The wife saw the news magazine that did the expose on the deaths endured by Greyhounds that got the rescue program started.
As a dog lover she knew that with a little love the Greyhound would adapt to living in a small apartment with 2 other dogs.
The fist day the retired racer comes home, after a few years of chasing a small white ball of fur for a living... They put the 2 pommies in the bedroom and let the Greyhound have the run of the house. Once he relaxes they take the muzzle off, and the Greyhound nods off. About this time one of the pommies pushes open the bedroom door and comes bouncing out into the living room, awakens the sleeping dog...
You don't want to know the rest, but that Greyhound thought he finally caught the rabbit.