The ADA has limits. Businesses are not required to change their policies and procedures in any way that would cause a “fundamental alteration” in the nature of their goods or services, would undermine safe operation of the business, or would cause a “direct threat” to the health or safety of others.
A "fundamental alteration" is a change that is so significant that it alters the essential nature of the goods, services, facilities, privileges, advantages, or accommodations offered. For example:
As a rule, people with disabilities may not be excluded from any services or be isolated from other customers unless it is necessary for the safe operation of a business. If legitimate safety requirements make it necessary to exclude or isolate a person with a disability, they must be based on actual risks, not on stereotypes or generalizations about people with disabilities. For example:
Staff are not expected to abandon their duties in order to provide assistance to a person with a disablility, when doing so would jeopardize the safe operation of a business.
A "direct threat" is a significant risk to the health or safety of others that cannot be eliminated.