I've several instances where people moved in, played the role, took people for money, possessions, then moved on down the line.
I've heard of a few "professional widows" in the borg that do that, a guy I grew up with, his father was a widower for less than a year, he was telling them that there's a sister that keeps pestering him and he really wasn't interested in her. A few months down the road he tells the family they're getting married. After a few years he got sick and died, she made sure everything was in her name and not his two grown kids, she didn't even show up at the funeral. Guess she was on her way to the next Congregation to find the next "fine, spiritual brother who just lost his wife"