This is normal for Detroit, isn;t it?
Actually, this is small potatoes for Detroit. They had something similiar a few years ago in downtown Detroit at Cobo Hall, with the mob being about ten times the size of this. What was being given out were applications for a lottery of about 500 housing subsidies. At the far end of the "jungle grapevine", it was "Obama is giving $5000 from his secret stash to anyone who shows up".
Some just robbed other people standing in line, or selling copies of the application for $50. Street gangs were unable to establish a truce among themselves while waiting in line. It took reinforcements from some of the suburbs, mounted cops, and judicious use of OC spray and tasers to calm things down.
By moving this event towards the edge of Detroit, they at least cut down the riot by a factor of 10, which I guess can be considered a partial success. :)