The supernatural world in the Buffyverse tends to do a pretty good job of keeping its existence a secret...even when it's trying to consume the world. I still say Wolfram & Hart has a mystical MIB division.

Now that you mention it, I do remember Lilah being stabbed in the throat. Hence the neck scarf, if I recall. I also seem to remember something about her holding herself together mystically? I guess I'm mashing memories, though. Joss has done some rather creepy stuff, though, hasn't he?