It was nerfed long time ago, after complains it happened too often. At least it was told to me when I was buying the pack and asked about it back then.
I still get those in San Myshuno apartments, pretty often too.
"mightysprite;c-18325981" wrote:
What is supposed to happen during a vampire breakin?
they just sort of wake up your sim , drink plasma enough your sim's energy is on red, then leave. Your sim passes out in the floor, similar way they do if not get to bed on time, has bad moodlets for some time and markings in neck.