MLB, the NFL, NCAA and NASCAR have orchestrated FAA Temporary Flight Restrictions designed to prohibit access to public airspace around their stadiums and venues within a 3.0 nautical mile radius, up to 3,000 feet above ground level, from one hour before to one hour after their events. They have done this, via their lobbyists in Washington, under the guise of National Security, claiming that such restrictions make the public safer. No terrorist is going to care about a TFR.
The real reason has been to remove banner tow airplanes from the airspace. These competitive advertising platforms threaten their in-stadium advertising revenue. In the mean time, thousands of businesses lose millions of dollars a year due to these onerous restrictions. Don't let these bad actors own US airspace.