No it's not a new behavior, I think it's something she's always sort of done, only if the doors are left open. She even peed on my cousin once when he was sleeping!!

She hasn't seen a vet, and she won't be. My cousin can't afford it right now, but that's another story.

And no there haven't been any changes at home.

One other thing. She is not spayed. Do you think this could have anything to do with it? If she were a dog I would say it's a dominance thing, but I don't know about cats and cat behavior.