It's more than a random person off the street would know, but not more than a [Mage]-school graduate could say. Ferris does not object.

"That's a strange way for it to work. Do a lot of your spells work that way? Anyway, very important people go around with anti-divination wards or have their homes and workspaces warded, but most civilians don't, even when there are trade secrets or confidential information to protect, because it's not worth the expenditure—to ward, or to scry in the first place. And it's illegal to scry inside private property most places, though it's obviously hard to enforce."

"Being resistable without necessarily being noticeable? Most spells that aren't themselves noticeable and target a person work that way there. ...that does sound hard to enforce."