My guess is this homeowner is fighting back on repeated graffiti attacks. And I also guess that he grabs whatever bucket of paint is handy! The overall effect is kind of interesting, don't you think? Certainly it's better than gang tags!
I'm a transplanted New Yorker who loves the Tucson climate. On New Year's Day I have a bit of fun calling my (snowbound) east coast friends to announce that I'm drinking coffee while sitting on my patio. (: