The same sort of thing happened to our family when we sat in the handicapped viewing section for the SpectroMagic Parade on our first ever evening at the MK. It was a busy Sat night; the only night of our trip that we could catch Spectro. As we sat eating our hot dogs at Casey's, people were already lining up for the 7pm parade at 5:30! I remember saying to my DH, "Wow, I'm so glad that we can use the reserved seating for this, can you imagine (DS) trying to sit for an hour and a half waiting for a parade?"
Our DS is profoundly autistic, and was 5 yrs old at the time. He was, and is, very hyperactive and because of his excitement, and was uttering a constant stream of loud, random, vocalizations while he flapped his arms wildly. It seems pretty obvious to even the casual observer that "something is not right" with him.
We made our way over to the handicapped seating, showed our Guest Assistance Card to the CM, and were promptly admitted to the roped-off area. We wedged ourselves between a garbage can and a lamppost, behind a couple of rows of wheelchairs and eagerly anticipated the parade.
Understandably, as parade time drew near, the area became filled to capacity and the CMs were obligated to turn away families who were arriving, (about 5 minutes before parade time, mind you). They were directed to another reserved viewing area by the CMs.
Well, you would not believe how many other "guests" and their family members actually told us, "You can't sit here, this is the wheelchair section." Or even better, loudly commented to each other, "I can't believe the nerve of some people!" Now, these were not even the ones who were turned away, but, rather, the ones who were already comfortably seated. Some even complained to the CMs who, to their credit, defended our "eligibility".
After several minutes of this, my DH was about ready to punch someone in the nose! When the next busybody made a coment to me about us sitting in the "wheelchair section", I had had enough. In a loud voice, I told her pointedly, that this was NOT a "wheelchair section", but a "handicapped section", and that our son WAS handicapped even though he was not in a wheelchair, and if she had a problem with that, she could speak to the CMs, or call Security!
I suppose it was so upsetting at the time because it was so unexpected! It really was very rude of these total strangers to think that they had the right to tell us to get lost, and it was a terrible start to our vacation. We truly appreciated and needed the reserved seating and it made us very uneasy about using handicapped seating for the rest of the week.
Now its three years later and I have developed a thicker skin, I guess. When people stare or make unkind comments about my son, I don't even bother acknowledging them. Their ignorance is their own punishment. And I've got more important things to worry about!
I still think that WDW is just about the most inclusive place that we have ever known, and we come every year for the most wonderful time!

to all of you dealing with non-apparant disabilities!
Kathy