Wayne:
It might be a little hard to pinpoint when architects actually did things like that on purpose because it seems like few of them actually mentioned it or wrote about it. In my opinion, the reasons why are sort of obvious. To state those things is a bit like revealing the "mystery", isn't it?
But ironically the architect I've seen mention it and even write about it is Tom Fazio, particularly in how he occassionally designs "dips" to make the target look closer than it actually is!
Since bunker faces or bunker fronts in the old days were sort of rudimentary, as in their construction basically being earth dug out and thrown right in front of the excavated pit, the reality of visual deception or perceptual miscues (hiding what's directly behind the raised face) probably just sort of happened and then architects and golfers began to notice the visual effect of it.
We certainly do know Flynn used this technique all the time but I can't recall if he ever actually admitted it much less put what he was doing in writing.
Certainly Mackenzie and his various applications of military camouflage in golf architecture understood he was doing things like this architecturally. This type of thing could be one of the primary reasons Mackenzie was always known as an architect whose courses often looked harder than they really were----the virtual opposite of Donald Ross's style!!