I have found a link for the article in the Washington Post.
\It appears that WTOP left out the fact the police will ask permissionto search houses.
From the Post article.
“D.C. police are so eager to get guns out of the city that they’re offering amnesty to people who allow officers to come into their homes and get the weapons.”
http://www.washingtonpost.com/wp-dyn/content/article/2008/03/12/AR2008031202717.html
Or put another way: "Let us in and we'll just take the guns. Make us get a warrant, and you go to jail"