I have to agree with everyone else. What the GAC does depends on the person who has it-so giving a blanket answer is not going to happen. The accommodations my son gets for it is completely different from what SueMN's daughter gets, or Cheshire Figment. Just as each of us is unique, so is the GAC, to an extent.
Mobility issues have been addressed in many of the ride queues. For instance, my SIL and MIL use
ECVs. At MK, they did not have need for the GAC and were able to enter many the queues with us. My son's issues are sensory and as a result, his GAC was used more frequently.
I've developed some mobility issues (cannot stand still due to severe heel pain) and I'll probably have to get my own GAC in the near future. Mine will be different from my son's.
I'm sorry I'm being vague, but there is no cookie cutter response to what the GAC does. For some, it means a waiting area that is covered. For others (like my son) it means waiting in a less crowded area, for others it may mean that their stroller should be recognized as a wheelchair.
One thing it is not: A 'go to the head of the line' pass. I've waited longer in a side area (Peter pan, for instance) than we would have in the normal queue.
The main purpose and the reason why we do this gladly is that if my son is not overstimulated by noise and crowds in the line, we'll prevent a lot of his meltdowns.
Hope this helps.
Suzanne