Was looking though some of the Canadian agency sites and noticed that one of the agencies (Girls Generation) tag the ad photos as either Visual Reference or 100% Real. Have not been there for a while so cannot confirm just how real or how representative the reference might be but interesting to see.

can be pretty wide.  Being able to say that the photo looks like the same girl, but with the face altered or blurred to protect her identity, compared to saying she has two arms and two legs just like the girl in the photo can make all the difference in the world.