This is copied ( with a bit of editing to remove GAC information) from the disABILITIES FAQs thread.
It has ALWAYS been Disney's policy to tell guests who say they can't stand to wait in line. They had not been enforcing it recently and had given out GACs to guests who insisted they had trouble standing.
The DAS ((Disability Access Service) is going back to saying the accommodation for issues with stamina or standing in line is to use a mobility device and in all likelihood, guests will not get a DAS for stamina, standing or walking issues.
I have problems with standing in line or with walking. Why did Disney suggest a wheelchair of ECV (motorized scooter)?
Disney calls these "Stamina or Endurance Concerns" and the official response is to suggest a wheelchair or ECV.
If the person has problems with standing in line or with walking, a wheelchair/ECV would be a better solution than a disability card.
A trip to Disney includes a lot more walking than just what you do in line.
There will most of the time be no place to sit while in line and no guarantee it will be available only for people with disabilities.
The distance walked is
not usually less with a DAS than without one, so someone who is concerned about walking or standing would do better with a mobility device and/or planning their day to hit the most popular attractions at the least busy times.
Most of the lines where you will actually standing still for long periods are the lines for shows and movies. Because those 'load' large numbers of people at a time, people have to stand waiting for the next show to 'load'. Having a Fastpass or a DAS won't change that - if each show is 14 minutes, you are going to be
somewhere for 14 minutes. In many shows, much of the time in that place will be a preshow area. If you don't have a mobility device, you will generally be standing during that time.
With an ECV or wheelchair, you will always have a place to sit and can conserve energy for fun, instead of just getting around.
Having a mobility device doesn't mean you have to sit in it at all times. You can get out and walk for a while.