This is an interesting debate and the issue has come up for me again recently where a stranger asked me the question right out of the blue. When I was repeating my experience to an acquaintance, their response shocked me. Hence a debate on the topic was opened up in my mind!
Is it ok to ask someone about their disability?

A good question, I never ask for several reasons 1-its none of my bussiness 2-its probably not something the disabled person needs to be reminded about 3-its potentially going to be a negative story that wont do me or the other person any good talking about it. Best just to ignore there disability and focus on the positive.
All very good points! Well said.