I can see no positive spin that can possibly be placed upon what Katya and Seann have done.
Kristina Rihanoff felt the effects of the disapproval of the viewing public and was given ever worse dancers as partners by the BBC, I think Katya will experience the same. All those brownie points she earned after dancing with Ed Balls and then winning it last year will drain away.
Why on earth would they both do this? Do they have no respect for their partners?