Of course after making the above post one of my less moral vampires did stage a breakin and did attack one of my elder sims. It might have been quite interesting, actually, as he was in a poor physical state at the time and it would have created an interesting and tragic arc with him having killed her and all that - but I still had use for him so I saved him. I actually welcomed it, though. It was a nice added twist to the story so I wouldn't mind if it happens again sometime. This particular vampire sim is born and bred in my game and has all the negative traits you can imagine, so it makes sense within the game canon that she would behave like that...
