Let me put it this way:
'Pureblood' humans
I figure NPC humans are this as well as the handful of PC ones. NPC blood thieves, sorcerers and Paladins are all yellow enemies, so it stands to reason that the little white dudes are pureblood - that is to say, unclassed humans. These guys (or girls. Whatever.) probably won't know about vampire society or anything bordering on the supernatural. They're basic 9-5 humans, really. They have their gin, they have their smokes and they're ignoring the boot stamping on their face for eternity /Orwell.
Exposing them to vampire society/the supernatural in general should be a violation of vampiric secrecy.
Blood thieves
This one's pretty simple. By (dubious) virtue of the simple fact that they're blood thieves - which is to say humans who drink the blood of vampires - they already know about vampires, vampire society and the supernatural in general. For them to not know about it would be rather like saying that I'm not aware of steak or where it comes from. Logically, they simply have to know about vampires already, and so:
Exposing them to vampire society/the supernatural in general should not be a violation of vampiric secrecy.
Paladins
According to the Path wiki, these guys are basically vampire hunters with powers that allow them to better combat the undead. Or, y'know, vampires. Especially vampires, according to the wiki. It'd be a bit daft to say that vampire hunters don't know about vampires. So:
Exposing them to vampire society/the supernatural in general should not be a violation of vampiric secrecy.
Sorcerers
This one is a little trickier. As sorcerers they're clearly aware of the supernatural. They kinda have to be. If they're into the ritual side of things, they're also aware of the fae, so a logical follow on from that would be that they're also aware of what the fae hate - vampires. But not all of them are going to be doing rituals, potentially, so to assume that they all know about vampires would be a bit premature. That being said, sorcerers do have the Dark Theurgy power, the description of which states:
So it's a safe bet, essentially, that they know about the existence of vampires. Or that power would be a little confusing for them. In short:Using one of your physical weapons, attack any vampire no matter where they are. Cannot cause critical hits
Exposing them to vampire society/the supernatural in general should not be a violation of vampiric secrecy.
Basically, what I'm getting at here is that the way the violation system works should have a little tweak to better reflect the RP mechanics of the class set up for humans if that's at all possible. If Ven shares his ID with a blood thief, that shouldn't be a violation. It shouldn't be a violation if he shares it with a Paladin. It shouldn't be a violation if he uses his powers in plain sight of either class. Or if anyone else does.
Discuss away.