It sounds like she may have you trained. I would suggest that (even though it's a pain) you leash her and take her out-or go out with her, bring a flash light, and see if she DOES go. Try this for a few nights. If she does NOT go-she has YOU trained-under her control. If she does go,then you might try limiting her drinking a few hours before bedtime. As long as you are sure she has no medical problem symptoms-this might be HER "power trip!" THEN perhaps you will have to decide WHO is the alpha dog in your home!Perhaps someone with more knowledge may have a better idea?