I actually didn't believe this when I saw it...(I've never heard of 'The Examiner') so I had to check it out myself. I was convinced when I saw the DC Police page talking about it! It is amazing how little media coverage there was of this.
So the question is...are the checkpoints to keep 'criminals' from entering the neighborhoods (which is what the police claim) or to make sure that the neighborhood's most desperate residents have no choice but to prey on their neighbors rather than going uptown to mug people who actually have something worth taking?

http://www.examiner.com/a-1423820~Lanier_plans_to_seal_off_rough__hoods_in_latest_effort_to_stop_wave_of_violence.html