"It's a very evil lair," Crowley says, quite seriously. "Stupendously evil. Don't know if you've got the stomach for it, angel. You might be overcome. Enough to make your wing tips turn grey."

Which does make it, based on that, very evil indeed as blanket lairs go. Still..

"Course, that might mean you're obligated to inspect it."

Angelic duty and all that.