I am sure it is legally correct (as the law currently stands) but is this justice? Even if this woman did "egg on" her thug of a boyfriend, is she responsible for his actions? After all, if she had "egged him on" and he had ignored her, her actions would have been no better or worse. The only factual difference between the two scenarios is in his actions, his choices. For which, of course, he should be held fully responsible.
I remain convinced that (save for such things as falsely shouting "fire" in a theatre with malicious intent) only actions, not words, should be punished. You may say that a mob boss who orders a hit is guilty despite only uttering words. But he is guilty because of the power he holds to compel obedience (or the money he offers to secure it). To equate this harpy with a mob boss is ridiculous. She could, and should, have been ignored.
The very concept of "incitement" is a flawed one. And it is a flawed concept which is in course of being rapidly and dangerously extended. Our legal system believes there are people so dumb that they will hate whole races if "incited" to do so. What tosh. They have the choice to hate or not hate. And if they hate, then they have the choice whether or not to harm the objects of their hatred. I hate Gordon Brown, Harriet Harman and David Blunkett with a veritable passion, but until I act upon it there's no crime involved.
To convict her, the jury must have believed this woman incited her mate. I am sure the jurors were right to disbelieve her story that she was "shocked" and shouting "stop." I am sure the thug's evidence that she didn't want the victim harmed was simply his attempt to save her. They lied, but the fact remains - whatever she was screaming for him to do - he could have said "no." Punish him for his actions by all means, but don't insult him by suggesting he lacked free will. The impulse to violence was his and his alone. She is a total irrelevance.