Are sports arenas becoming the battleground for civil protests?

A protester at a Cardinals-Brewers Major League Baseball game unfurled a banner that featured a Cardinals’ mascot holding a sign saying, “Racism Lives Here” and “Stop Killing Us.”

The acquittal of former police officer, Jason Stockley, in the shooting death of Anthony Lamar Smith in St. Louis touched off several protests in recent weeks.

Have professional sports arenas become the new battleground for civil protests?