Harry, I would have gone with the British version of the two "Carefree" examples if given a choice, so I think wiki isn't entirely accurate on this. And since I am currently studying English I feel I know what I am talking about. To me the comma and period go with the sentence, not the quoted material. And that is how we were teaching it last year.
No wonder we see so many mistakes in books, if there are VERY fluid rules to follow.
I'm not bothered by small mistakes in books, but when misplaced commas change a meaning or make that meaning unclear I become irate. Or they use the wrong words, or even tenses of words.