Normally I enjoy the new story progression that has Sims moving around and out of town. But for some reason, my extended family has left town twice! I move them into a vacant house next door to the main house so I can see them easily and they will be close by. The first family moved from this very nice house to a smaller house across town, so I used Edit Town to move them back next door. A couple of Sim days later, the house was empty again and this time they moved completely out of town! It even made the paper. I can still call and invite them over, but I can't go to their house to visit. I put a second part of my family in that same house next door and after a few Sim days, they had left town, too!
I thought someone here on the forum said that if it's a family that you've actually played, they won't leave town. I played both of these families, but they left anyway. It's annoying because I'm trying to get the family deeply rooted in Sunset Valley. It's bad enough when they don't have children of their own, but then the ones who DO have babies move away! Argh!!!