I think anything is possible, really.
I don't have any ghost stories, but my cousin Lisa has one of the best I've heard.
A couple years ago, while her husband, a U.S. Army officer was deployed to Iraq, she and her two kids were staying with the husband's family in Arizona for a few weeks. One night her little boy woke her up in the middle of the night and asked for a glass of water. She got up without turning the lights on and walked down the hallway. At the end of the hallway, she saw the shape of a person walking away from her. So she was so sure it was her mother-in-law that she addressed her by name. The shadow stopped moving and disappeared. My cousin isn't rattled easy, so she got the drink and went back to bed. The next morning she told her in-laws what happened, and her husband's sister showed disbelief and pressed her for more details - she eventually started crying because as a child she use to see the same figure, but no one believed her.