Random "Stranger" sims keep coming into my apartment.

Sims that my Personal sims do not know, they have never met just keep coming into my apartment in San Myshuno (This is my current play, I do not know if it happens in houses or in other towns). They just walk right in without knocking. My sims can be in bed asleep and some random sim (child, teen, YA, adult, elder) will just walk in and start using the computer or having a meal. Since I don't know them, I have to introduce my sims before I can even ask them to leave. It's really annoying. I can lock to only household which does stop the intruders, but I personally don't enjoy gameplay with locked front doors. 

(No Mods or Custom content)