Well if you can sue a bakery for not selling a cake to a gay couple then this should be fine too.
Busting business owners for banning guns:
A bill introduced in January by Colorado state Sen. Kent Lambert (R) would require businesses open to the public to either allow concealed carry permit holders to bring their guns inside or hire armed security officers (one for every 50 customers). If a business fails to comply and violence on the premises ensues, the business would be held liable for any injuries or deaths that might've hypothetically been prevented by an armed citizen. "There's a responsibility for businesses to provide some security when they have asked people not to defend themselves," Lambert told KOAA News 5.