Also, any penalty short of death is going to be relatively little actual deterrent, in the long run. It'll encourage vampires to make a strong attempt to convince their mate, but if that isn't possible they will be quite willing to simply kidnap and turn them, in the sure knowledge that they will forgive them once turned, and make sure that the bond is fully established before the Empire intervenes so that they aren't serving N years hidden in the absence of their mate.