It's all part of that "tough on crime" stance that a lot of liberals (including Hillary Clinton and her probable challenger, former Baltimore mayor and Maryland Gov. Martin O'Malley) took back in the 90's. Blacks are routinely arrested for minor offenses like loitering or littering, or even jaywalking. it's a good way to boost the numbers and make it look like the government is doing something about crime.

Much the same thing is done here in Tulsa (or it used to be done, until I and a few others raised such a stink about it down in City Hall). Hang around low income housing areas, and ticket people for things like littering or jaywalking. Nine times out of then, the poor people won't pay the fine and an arrest warrant will be issued. Then, two or three times a year, the cops go around arresting people for these old warrants. It doesn't do anything for crime obviously, but it sure helped the cops when it comes time to renegotiate their pay with the city. And, of course, it helped make the mayor look good right before an election.

Onward and upward,
airforce