As the last one in the thread who posted a picture with a graffiti back drop, which I guess spawned the initial question, I feel obliged to point out that there is one reason to choose such a background that has not been mentioned: I like graffiti. I know a thing or two about graffiti both as an art and a lifestyle and I happen to live in a city with a pretty healthy graffiti scene. I sometimes choose to use graffiti as a background in the same way as someone might use any other motif of interest and/or beauty. Street cred does not play into it at all, I lost any ambitions in that department decades ago.
It depends of course on the basic premise for the picture. Many in this forum take pictures primarily to document a fit, which I suppose is actually more in line with the theme of the group. I am lucky enough to have a very talented photographer who is willing to take my pictures, but that also means that her ambition is slightly different than "just" documentation. As a consequence my pictures may not be as helpful in terms of examining a fit, but hopefully they can give a sense of clothes in context.
Some posters on this thread might not be as familar with "Wall Scouting" as other posters are. As a practicing Wall Scouter, I hope that I can encourage others to become Wall Scouters.......