
I did this when a neighbour died, and no relative wanted the old guys dog. I was asked to look after it while they found a home for it.
Went round at 7am and intermittently throughout the day. Last visit around midnight. It went on for weeks, and I gradually started bringing her round to my place (although they didn't know.)
It ended up that she only actually went home to sleep! After 8 weeks they phoned to tell me they had found a home for her. I told them it was too late, she lived with me now. I couldn't wait to pick up her bed and collar and lead, and shove their key through the door!
But yes, it can work. A dog is better in its own environment than being stressed out.