Have never asked or thought to ask in normal real life situations.
I once was in a relationship for 18 months with a guy, who was a tall guy, but ended up with the smallest I'd ever seen (about 5"). We were already in a relationship when I found out, so I didn't cut and run.
He had small hands and fingers too, so I'm more aware of men's hands now, lol. If I meet someone who I liked and had small hands and fingers in the future, I'd try and make a joke about how some folk say there is a correlation and see what his response would be. However if I liked his personality and felt he had potential as a boyfriend, then size wouldn't be a deciding factor.