The flight home from Los Angeles is full, and my wife and I are seated next to a woman in the window seat who is cradling a lap dog that is part Chihuahua and part too-big-for-a-lap.
"He's a service dog," she says immediately. "I took off his vest, but if you want to see it …"
No need, I assure her. I don't ask a pregnant woman if she's pregnant. I don't ask an old man if the young woman on his arm is his daughter. I don't ask if folks who park in disabled-parking spots are really disabled. And I don't ask if a woman with a service animal is pulling a scam.
The woman apologizes for the excessive shedding that soon becomes noticeable on my wife's black pants. She apologizes for the drink spilled on my wife. She apologizes for the two or three times the dog gets a bit excited and barks.
Of course, I am curious as to why she needs a "service animal," but that is none of my business. I only know that the dog makes no attempt to stop her from downing five vodka tonics, although I suspect that you could train a dog to bark whenever an owner's blood-alcohol level tops .08.
The line between a service animal, an emotional support creature and a pet might not be obvious to most people, but the law is straightforward. The Americans with Disabilities Act defines a service animal as a dog "individually trained to provide assistance to an individual with a disability." That's all there is to it.
"If the animal meets this definition, it is considered a service animal regardless of whether it has been licensed or certified by a state or local government," the act says.
"People who have disabilities should not be denied access because of their service animals," says Annie Thompson, a spokeswoman for Illinois Attorney General Lisa Madigan. The ADA also has a provision allowing access by trained miniature horses.
Thompson urges people who believe their rights are being violated to contact Madigan's Disability Rights Bureau.
There have been stories of "emotional support" animals including cats, miniature horses, pigs, monkeys, turkeys and a duck all flying next to passengers on planes. But airlines can deny that privilege to some "comfort" animals, including "snakes, other reptiles, ferrets, rodents, and spiders."
Even service animals can be removed from planes and businesses if they cause problems, such as the case of a dog barking repeatedly in a movie theater.
While online businesses sell all sorts of official-looking patches, vests and documents proclaiming a pet a "service animal," that sort of documentation isn't necessary.
"You may ask whether the animal is a service animal and inquire as to what tasks the service animal has been trained to perform," the attorney general's website explains. "You may not, however, require identification documents for the animal or ask about the person's disability."
Nor can you demand to see the animal perform its service. Businesses must allow an animal if the owner gives "credible verbal assurance" that the animal provides a service.
Because there is no government registry, it's difficult to know how many service animals are out there, but online searches suggest there are tens, if not hundreds, of thousands. Courts have said elementary school students have the right to bring autism service dogs to school. Parrots for Patriots matches exotic birds with military veterans suffering from post-traumatic stress.
"There are so many invisible disabilities," Thompson says. "An animal also can be a stabilizing force, sense panic attacks or sense blood-sugar changes in people who are diabetic."
Any business owner who turns away a service animal is committing a misdemeanor crime in Illinois.
"Last year, we looked into dozens of complaints related to service animals," says Thompson, noting that most cases are resolved once people understand the law. "We err on the side of accommodating."
In the case of the woman who drank five vodka tonics, she did assure me that someone was coming to pick up her and her service dog.