I often get a lift to play Curling by one of my fellow club members, and I used to do this sometimes with a guy well into his '80s (he had to play using a stick that disabled curlers normally use).
This being a winter sport, it is often dark.
Annyway, there we were, hurtling along the M8 one evening and this guy suddenly announces that he'll have to stop driivng at night as his Doctor has told him it is unsafe for him, and indeed he cannot see things like he used too.
'Yeah, thanks!'
Thinks I, just as we round a corner and with no word of a lie, almost crash into the embankment of a turn off....
I arranged alternative transport after that, but the guy has now stopped playing anyway.