A.M.
My 3 year-old does the same thing and she stopped doing it as often after I put her and her 10 month old sister together in the same room. Before, I'd find her asleep in the hallway, on the floor in my room, in the living room recliner and outside my door. At first this happened every night and I would find her in the middle of the night and put her back. After a while I just decided to let her sleep wherever she wants to and it happened less and less frequently. Now, she still won't sleep in her bed, but she sleeps on the floor in her room and sometimes she climbs into bed with her sister. She seems to sleep just fine and my baby seems to sleep better with her in the room too. Maybe, they just feel the need to be closer to someone.