Is this the main bathroom ? Is it an option to take the door off completely (temporarily). It would be interesting to see how she reacts to this. I do positive reward training with my dogs, but am also a fan of the Cesar Milan style, which is to "correct" her the nano-second she even thinks about going to the bathroom. So you and her go near the bathroom, with her looking at you. The second she looks at the door your correct her (ie say 'hey' in a corrective tone). You may need to have a second person walking into the bathroom to get her attention to the bathroom, as you need her to do the behavouir in order for you to correct it. Anyway, just another suggestion for you to try... I corrected my dogs chewing of the remote this way... but these guys are soooooo stubborn sometimes it seems futile; good luck. Also, I would be careful giving her away, as she will likely have similiar issues with the new people and god knows where she will end up if its allowed to continue...