It's a sign that these businesses need to double up on their property surveillance. What's more detracting: a couple of cameras or a building covered in graffiti?

This is not new behavior, but it does indicate that this group feels comfortable enough to spend a lot of time spraying a building in a highly visible part of the city. That is the major problem here. These sorts of people aren't going away anytime soon, but they should at least be worried about getting caught.