I played many terms with roommates, both on dorm and residential, and never missed any activity from them. I had the romantic NPC bringing home a bf/gf only in dorm, but that is due to the random traits they come with. I had the said warning only once, and I know there were several plumbing needing a fix at the moment. But like someone said, that message can be cause by any needs in the red, such as Socials and Fun, which have nothing to do with plumbing. I don't know if that roommate moved out and got replaced, and if so it would be fine because I think it's more realistic if they actually move out from time to time.
What I have noticed, is that with any changes in the household, most bed assignments get wonky ad I must set all beds again. If not they will still go to sleep in any bed, but with several locked doors, it might cause some sleep need challenge.