To me it's one of those "How heavy is a rock?" questions. In a particular instance, I think anyone can answer it about themselves. But in the abstract, it's a lot harder.
Some people have issues with many or all things, and can easily answer 'yes'. Some people have no real issues and will easily answer 'no'. But there are a ton of people in the middle who have problems with certain situations and it's not an easy answer.
If you could answer "yes" without having to worry about repercussions, I would recommend that anyone unsure just answer that. But sadly, that's not the way the world works.
Everybody in the world can honestly answer yes they are disabled because of something. Yet the vast majority don't need special consideration to live their life. Even when someone does need special consideration what is important: Those bumps in the sidewalk that let a blind person know there is a road crossing ahead are critical to their safety - but they are very uncomfortable to someone in a wheelchair, sometimes to the point of being unable to use the sidewalk at all!
In short, the question is invalid. What is really needed isn't a yes/no response it is an appendix of what accommodations they have and already and then a blank of what you need. If you are in a wheelchair and the place already is wheelchair accessible then you are not disabled, but if the building hasn't be remodeled to wheelchair accessibility you are disabled. If there won't be a meal/snacks then your food allergies are not a disability, but if there are then it could be (could because some are you know what to avoid and can trust to find the something safe, while others are don't even have something in the same room).
But it is easier to have a yes/no question even though that is useless to everyone.
Some people have issues with many or all things, and can easily answer 'yes'. Some people have no real issues and will easily answer 'no'. But there are a ton of people in the middle who have problems with certain situations and it's not an easy answer.
If you could answer "yes" without having to worry about repercussions, I would recommend that anyone unsure just answer that. But sadly, that's not the way the world works.