That shouldn't matter, Athena - as an example, I had a Young Adult sim whose imaginary friend had grown up with her play chess with her friend before work. When the carpool came, she left for work, and the imaginary friend walked back to the bed that "belongs" to that sim (have you noticed that if you click on someone else's bed, "Sleep in Joe's bed" comes up as an option?) and turned back to doll form right next to it.