Actually there is. I noticed my sims can lock the door of a generic lot for anyone that isn’t part of a specific club, so i’m guessing if you make a club with just your sims as members, you can lock the door so only they can enter.
"invisiblgirl;c-17146074" wrote:
Heh - my Sim's been living on a generic lot, so there is no way to lock the door (and it's technically not hers, anyway). She had a visitor who simply wouldn't leave yesterday, even helping himself to her food and sleeping in her bed. She finally told Goldilocks to go away, but I think she broke his heart.