... If there are vampires there can so be Hogwarts!

The Volturi can't stop me from believing!
Moving on, *goes to check New Moon*
"...Marcus of the Volturi, in fact. The story claims he was martyred in Romania, still trying to drive out the vampire scourge. That's nonsense of course- he's never left the city. But that's where the some of the supersitions about things like crosses and garlic come from.
Father Marcus used them so succesfully. And vampires don't trouble Volterra, so they must work."
Carlisle never says if the mob got the true vampire they were hunting, so I can only assume he outran the humans, and therefore didn't die.
It seems that humans thought that they were killing vampires, so either the Volturi planned all the "vampire catchings" to spread the propaganda, or the normal vampires caught on, or the humans caught innocent people and thought this stuff worked. In the meanwhile while everyone was in Translyvania chasing Dracula, the Volturi were discreetly taking care of the real trouble makers.
I can't think of any other instances, but when I read New Moon again in the two hours I have to wait to see the movie (Ah, the joys of reserved seating. I don't have to stand in line with squeely Robert fans, thank Neptune.) I'll be looking for them. If you'd like to add any, you can, to prove your point.