I was skeptical of the NY Post story alleging that rich New York private-school parents use a service that lets them hire disabled people to act as line-jumping Disney World guides. Now Lesley, a Disney-obsessed local, has published a rebuttal pointing out that such a service wouldn't work well because there are lots of rides that can accommodate wheelchairs through the regular entrance. She also points out that the article claims that the wheelchair guide helped skip a 2.5h line for Small World, which sounds like BS, because Small World doesn't really get 2.5h lines. The whole thing is worth a read.
I've visited Disneyland and Walt Disney World with friends who had disabilities. I went to Disney World with my mom and a friend who were both in wheelchairs (my Mom had just had a hip replacement; my friend had a broken foot), and found that there were hardly any long-queue rides that offered any priority queuing to people in wheelchairs. On the other hand, I once visited Disneyland with a blind friend and her service dog in the late 1990s and found that people with dogs and their parties did go straight to the front of the line in most cases (I don't know if this is still the case, though).