It's people like that can completely turn a persons day around with just one sentence. It does seem to be older folks that pull of the charming persona compared to younger people.
I think it's really tied into how previous generations were socialized, both formally and informally. Civics class and etiquette aren't highly prized at present, even in very small ways. I can't tell you how many times I've encountered someone who has proudly told me in a formal dinner setting that they, "don't even know which fork is which." As an aside, I feel like such people are the ones keeping the Ugly American alive when they travel.
I would imagine also, that the truly charming individual would be able to pull off "the fork misunderstanding" with such aplomb, that others seated near him would happily offer the correct information and feel better for having been able to help Mr. Charming.
To be proud of such a lack of knowledge is equally as bad as being ashamed of it.