Do Vampires Visit Other Neighborhoods Autonomously?

What I meant by my post above is not using it as merely a stuff pack, but perhaps people like to play a vampire challenge and in another save a classic legacy. And I for one have read too many "they still came by my house" like posts to believe that they will just randomly leave you alone when you don't go looking for them. Thats where *I* would like a toggle, so I can decide per save if they spawn in that save or not. Waiting for a stuff pack doesn't make that happen.