I don't know...that seems to be about the dumbest voter fraud attempt I've ever heard of...probably just sample ballots.
It would seem dumb, but these are democrats we're talking about. In 2000, they assumed any ballot with more than one mark automatically went for that nutbag gore. They probably hope people wouldn't question an 'official' ballot even with markings, and send it in whereby they could consider it a kerry vote.