It's never happened to me, but it did happen to my sister a while back. She was about eleven, and was in love with Nintendogs. She was very attached to one pup in particular -- a husky named Lucky. She treated that virtual pooch like he was her own.
Now, one day, our aunt comes visiting and she brings along our six-year-old cousin, who asks my sis if she can play Nintendogs. She agrees, but gives her very strict instructions to not do anything with it except play with the dogs.