Charleyann, My mother would benefit from a GAC for not standing in the lines as well - but here on the disABILITIES board there was info stating that WDW policy was to tell you to get a wheelchair, as the walking between attractions was much more demanding than the length of the lines, or somesuch.
My mom's knees are bizarre, to say the least. She can outwalk me on basically flat terrain, but if she sits or stands still for too long, they freeze up and she is in severe pain. Thus, a wheelchair/
ECV would be the worst thing for her. As it is, I have to help haul her up and out of many of the ride vehicles, such as the IASM and Splash Mountain types. If she could avoid standing still in lines (you should see her try to 'pace' a bit when we are in one spot too long) she would be able to enjoy her day at WDW more.
My mom has been to numerous specialists, endured painful shots, taken medications that turned her inside out, and still has no relief from the pain. She can't even sleep a full night in an adjustable bed - she has an apparatus now to keep her knees in some elevated, supported position, with some other stuff going on as well. She gets about 2 hours of sleep, has to get up and move around, change the ice packs, etc, and then try to go back to sleep.
I feel like you jumped down my throat Charleyann, for asking a simple question about WDW policy.