I think it's not needed. Yes, there will be an abandoned family or two, so what?
Right now, with people coming in and trying a new game, it sometimes happens that a lot of families are abandoned early, but I think later on, when the game is more established, that won't be a big problem. And if it is, I can always add a simple piece of code that turns a family into AI on day 2 if the player hasn't logged in or something.