Well, she's only gotten worse. The howling routine has been supplemented by scratching the door. She really doesn't seem to get the point that she won't be let in. I'm a light sleeper, so even the scratching wakes me up. I've started taking a two strike approach. At the first scratching event, I go to the door and tell her no. She usually goes up the stairs. If it happens a second time, they have to go to their room.
Maybe she will learn? I don't know. Why does she even want to come into the room if Helmut's there? She's never been the brightest cat. I rescued her because she ran in front of my car and I had to brake to not hit her. It was in in an undeveloped area with no houses or businesses around, so I loaded her into the car.