I just got this pack, and my neighbor, Penny Pizzazz seems to be able to come and go at will. It's only day three, and I'm pretty sure my Sim didn't give out a key. This particular apartment gets "Noisy at night", so I tried taking a nap during the day, so I could paint/read/whatever, late into the night. She came in, while I was trying to take a nap & grabbed a book from my bedroom. Since I have a social bar to fill, it's not much of a problem, yet. However, it might be nice to know why it's happening. Is it a chronic bug that many people have, or is there something that triggered it? Like I said, I am just on day three of this pack, and I'm still very confused. Living in an apartment is a "lot" different.