Well, I always 0 them, but there are so many stat whores who are convinced that they'll be mass voted to pass anyway, they pass them as well to get the protect point. It's gotten to the point where mass voting isn't needed at all- it's left to the stat whores.
I'm not sure if there's any way to keep them from passing from an administrative point, but deletion is always an option, albeit an unpleasant one. I'd say that deletion should be saved for duplicate files, resubmits, and blank screen/single frame files for the most part, save for the occasional times that are out of the ordinary. It's up to the voters to keep the integrity of the portal. It's up to everyone who doesn't think they should pass to vote accordingly.