My sister did this and the it made the cat neurotic. He would be visibly unhappy when he had to go. Also, she had to keep water in the bathroom sink --otherwise he preferred to use it rather than the toilet.
I know of at least two schools that don't accept applications from their own graduate-- Stanford and Princeton. I guess they mean it when they say its a bad idea to continue your undergraduate institution. Does anyone know of other schools with this policy?