The local paper reports that Cleveland's mayor "recently vetoed an ordinance that would have criminalized some uses of social media and was aimed at curbing flash mobs." From Reuters:
The 21-year-old rapper, whose real name is Richard C. Baker, and two others who failed to comply were removed from the mall, police said. They were charged with misdemeanor disorderly conduct and released. Video footage posted online shows the event drew a large crowd. Some chanted "MGK! MGK!" as the heavily tattooed rapper tussled with officers.
"If havin fun with my fans and bringin the rage back to my hometown means I have to be arrested...then keep pullin the cuffs out," read a message posted on the rapper's Twitter account.
Video Link, below: "MGK"'s official video of the shopping mall takeover.