How do you think telling everyone that there are vampires would keep them safe? You really think any Joe Schmo with a hand-whittled stake can keep himself safe against bloodthirsty villains with super human strength? What about the rogue vigilantes who would go looking for trouble? Not to mention the folk who read too much Anne Rice and Stephanie Meyer and think attempting to find the vampires would be a good idea?
What would happen if the word spread? We'd have loonies by the score travelling here in search of the supernatural, making your job and mine all that much harder.