She knew whether an offense had been committed.
That doesn't prove it to anyone else, of course, but it doesn't seem like anyone is (now?) contesting the the offense in question was committed. Just that he got off free and she had no recourse. This is not a one time event, either, it's a pattern where the law fails to protect people in this situation and then throws the book at them if they take matters into their own hands. If she had not, do you think this dude would still be free? Or would the law have eventually caught up to him, after who knows how many more victims?
I'd say actually the only reason they backed down is because they realized they were going to lose and didn't want to risk their arbitration clause getting struck down in a court.