Stories of a short, fat bastard.

Well, if the person is sleeping in South America, where vampire bats are common, then yes, I'd say that's a valid concern. Vampire bats are all sneak-sneak-sneaky-*zwit* and lick up the blood as meek and quiet as possible. But if it's anywhere else, and a non-vampire bat bites you, it's going to be an "ARRRGH-RAWR-RAWR-GNOM-GNAW-BITE-CHOMP", and if you can sleep through THAT, then you've got bigger problems than rabies.