I thought this was an odd sign when I happened upon it a couple years ago. Odd in its wording. "Architecturally Controlled." And odd in its appearance. Apparently no one is "controlling" the "architecture" of this run down sign.
On a more serious note, I looked the neighborhood up online shortly afterward and found they have a very well organized home owners association with CC&Rs that are enforced based on what I could tell from the Crestwood Hills web page. It's a neighborhood of mid century homes and I applaud the residents for using the means of private contract to enforce the community design preferences rather than the force of local government regulations. When someone buys into a community they know what they are buying into, there are no questions about how they can modify their home, and there are no surprises. Some folks with more libertarian leanings prefer this sort of neighborhood by neighborhood private regulation over city zoning codes.