That sounds reasonable. Why would I have an issue with this person being late? I wouldn't. It's a great example of having a reason.

But I'm not psychic, nor am I a doctor of any kind, so if you expect me to make allowances without telling me what allowances you need then unfortunately you're out of luck.

If you expect me to make allowances for people incase they're ND then also you're out of luck. I'm going to ask you why you're late, I'm going to react to what you told me - anything you haven't told me is unknown.

That some people want to paint me as unreasonable because I want people to be on time, unless they have a good reason not to be, is naive and immature.