Yeah, it's a feature, but it's kind of a ridiculously dumb one honestly. They need to either SERIOUSLY decrease the radius at which guests get annoyed by them, and make it horizontal only(i.e. they won't acknowledge it if its above or below them), make it based on viewability, i.e. line of sight, or just get rid of this mechanic altogether. It's an annoying, pointless mechanic that is literally just extra micromanaging and it honestly makes no sense. No one who actually goes to a zoo is going to have their entire experience ruined just because they happened to catch a tiny glimpse of a staff building, honestly.
At the LEAST we should be able to turn it off for sandbox...