Here's a subject that's near and dear to my heart, because it effects the friend I'm traveling to Disney World with: the Guest Assistance Card (GAC).
The Disney GAC aims to assist people with invisible disabilities. This can run the gamut from being on medication that makes you too sensitive to sunlight to having children who are incapable of handling long waits in a crowded line (due to certain developmental / psychological disorders; I'm not talking about cranky toddlers). My friend has had a serious infection in her leg that left her blood circulation fairly impaired in that leg. She is not allowed to stand up for lengthy periods of time, but has no mobility issues that require her to use a wheelchair or "scooter." She walks just fine.
Disney makes the GAC easy to obtain -- a great benefit for people who need it, though I suppose it's possible it is also easier to abuse the system that way. Nevertheless, it's nice not to make a person who really needs it jump through hoops to get it. This is a vacation, after all. It's bad enough you have a medical problem on vacation, it shouldn't be complicated by making you fill up reams of paperwork or answer too many personal questions.
To get the GAC, a person has to go to any Guest Services location in any of the parks and describe their issue (or child's issue) in general terms. The actual bearer of the GAC has to be there, even if it's a young child. So I couldn't ask for a GAC for my friend if she were still sleeping at the hotel and I was trying to be nice to her.
Once you describe the problem, a GAC will be issued with appropriate instructions on it (there are several categories for GAC instructions, depending on the person's need). You do not have to present a doctor's note or a prescription label. The Guest Services Cast Member will issue the GAC according to your description of the problem (they may ask you some questions to clarify the issue). Remember that if you get the GAC for someone else, they have to be there with you.
Guest Assistance Cards are good for the entire length of stay for all parks. You only have to request them once at the beginning of your stay. They are good for the entire party traveling together, so families and friends aren't split on rides.
The GAC may allow the person a quiet waiting area, a wait area in the shade, or the ability to move ahead in the line if a Fastpass is not available. The GAC is NOT a "go to the head of the line" pass, and the carrier (and their party) would still likely have some wait, though a probably shorter one. Disney Cast Members may direct guests to obtain a Fastpass if one is available.
Children on Make-A-Wish trips have a special version of the GAC, obtained through Make-A-Wish, and they will go to the head of the line due to their special situation.
The GAC tends to irk people who are overly judgemental. It's easy to see why a wheelchair-bound person requires special accommodations, but people using the GAC tend to get dirty looks from some people, because their problem is not obvious. Maybe there's a lesson in humanity and compassion in this. Ask yourselves honestly what your reaction would be if someone who looks healthy got what seems like "special treatment" from cast members while you have to stand in line. Next time, give these people the benefit of the doubt, or count your blessings. Waiting in line is a small price to pay for being in good health.