I'm just chiming in on some other service animal points - if you'll excuse the pun, I have no dog in the fight, but working in the medical field I have seen MANY types of service animals you might not expect.
There are service dogs, and that's what most people think of when they hear "service animal". Yet, there are cats as well, even monkeys and miniature horses. HOWEVER, the current definition from the Civil Rights Division identifies only dogs and miniature horses as service animals under ADA. The animal must be performing an actual task for the person, and not just be a "comfort animal" (as in, helping the person feel calmer, for example.) Not saying they're not as important...just specifying the legal definition (as of 2010).
Those tasks can be very diverse. Service animals can guide the blind, sure, and others have mentioned alerting the people to seizures or fluctuations in blood sugar. They can also do simple tasks, like turn lights on or off, retrieve dropped items, alert a hearing-impaired person to noises, or even dial 911 if the person is unconscious (yes, it's possible - usually through a speed dial button).
I have a friend whose young son's dog is trained to do several things for him, in fact. She sleeps in his room and monitors his sleep disorders (she wakes him if she can or wakes his parents if she can't), is tethered to him outside the house so that he doesn't go somewhere dangerous, she is trained to pull him away from situations where he is becoming agitated (like crowds) and calm him, she is trained to search for him if he becomes lost, and probably a few other specific situations I can't remember right now. Before they got her, the family was unable to do something as simple as go grocery shopping. Now, they are planning their first ever Disney vacation.
Disabilities aren't always visible, and service animals aren't always obvious. But yes, they do have a very important place in people's lives. Kudos to
DCL (and Disney in general) for being so good at recognizing that.