The bottom line is, you live by the contest, you die by the contest.
You can't hold a contest to drum up interest in your new presenter, and then stiff the person who wins because they're not your favorite candidate. If you want that much choice in picking the person, don't hold the contest.
Sadly, there's really not much recourse if Pokernews screws Sarah here, and in the grand scheme of things, the poker community won't give a shit. But it would still be wrong.