Sport Pilots who have never gone in for a medical exam obviously can't fail the exam. So if that person complies with each restriction and limitation imposed by that person's driver's license and any judicial or administrative order, that pilot is good to go.

There is the catch all "not know or have reason to know of any medical condition that would make that person unable to operate a light sport aircraft in a safe manner." But of course that applies to all pilots anyhow.

Say an 80 or 90 year old allows their whatever class medical to expire. They can then exercise the privileges of a Sport Pilot as long as they comply with their drivers license and not know of anything medical conditions preventing safe flight.

Unless I get access to their medical records, which I don't believe I have the legal authority to do, how can I deny someone flight training just by looking at them and thinking, "they look too old, too fat, too prone to this.., etc." So I'm left to finding objective, observable actions or inactions on the behalf of the student to determine if they are neglecting to self-certify their medical airworthiness.

For example, I've flown with older gentlemen who have not been good to their bodies. I see consistently slow reactions and repetitive mistakes. So this is what prevents me from soloing these folks. I'm not gunning for people based on first impressions. But I am looking for safe behavior patterns.

And please don't take this as an attack on your post just food for conversation.