If customers or visitors becomes belligerent, a business can ban them from the premises without running afoul of disability discrimination laws, even if the individual is disabled and the disability contributed to the outburst.
Recent case: Peter, who has difficulty communicating clearly because of a disability, was banned for a 24-hour period from the public area of a business. He tried to sue, arguing that the ban violated the ADA’s public accommodation provisions. But the court said his claim under the circumstances was frivolous. (Rickmyer v. G4S Secure Solutions, No. A16-0664, Court of Appeals of Minnesota, 2016)
Final note: Employers sometimes forget that the ADA and Minnesota’s equivalent disability discrimination law also protect disabled customers from discrimination and require that places open to the public be accessible to disabled individuals. That doesn’t mean you can’t at least temporarily ban a disruptive individual.