They are stuck between a rock and a hard spot. However, it isn't impossible to deal with. Landlords that want no pet policies have come to realize that insurance policies that skyrocket if pets are allowed provide an unreasonable accommodation provision when a dog is allowed on their property. As an unreasonable accommodation they can legally deny the dog (which by its presence would cause business expenses to rise unreasonably through an increase in insurance premiums). I suspect airlines may self-insure and may be unable to pull this off. Stores? As they have to deal with the bio-hazards presented by dogs to their clientele (in the form of waste, aggression or allergies), this is going to become more and more of an issue. Some businesses may outright ban them (using the unreasonable accommodation provision) and others may provide a separate facility where the animal may be hosted until the owner is done with their business.