I will be the lowly voice of dissent and say I wouldn't advertise my disability while on vacation. Granted, I am not a parent to a disabled child, but I am a disabled adult who's been disabled since childhood. I'm a paraplegic. If someone stares at me, they stare. I usually don't even notice. I will never see these people again, why should I care?
The only time I addressed a "stare-er" was in a restaurant once. A woman at a table next to us kept turning my way and literally staring holes through me. I kept asking my husband if I had a booger on my face or something. Finally I looked at her and excitedly said, "Keep staring, I might do a trick!!"
She finally knocked it off. Never did figure out why she was staring.
Anyway, like I said, I don't feel the need to advertise my disability. If a stranger wants to know why I'm in a wheelchair, I'm more than happy to explain to them. Sorry to be blunt, but if my mother had put a t-shirt on me that said, "5 out 10 children will be injured because of drunk driving. I was one of them," when I was a child, I would have been pretty embarassed. My disability doesn't define me. I'm not a victim and I'm not a statistic.
Sorry, just thought I would offer another opinion.