I ask because I distinctly recall that my feeling upon reading the article nearly 30 years ago was one of bemusement. I mean, I was, back then, very much enthralled by nearly everything Gary wrote. He was, after all, the creator of AD&D and his word on the subject was Law. But a list -- a definitive list, no less -- of what creatures qualified as "persons" for the purposes of certain spells? Why was this necessary? Did anyone really wonder whether a swanmay could be charmed or an ogrillon held? Was this even an issue at all? Maybe it was needed in tournaments, I don't know, but it was never an issue that came up in my gaming groups.
Just as interesting as the list Gygax provides are his closing comments in this article. He says the following:
If you, as a player, are grateful to have this expanded list, your gratitude is certainly appreciated but keep in mind that it is a mixed blessing. Players must attempt to remember the list of creatures affected by charm person and hold person, for when it comes time to cast a spell, the DM must never allow them to consult their reference works except for the Players Handbook. On the other hand, the DM can use any reference source at his disposal (including articles like this one) to check for desired information.Now, there's nothing beyond the pale in what Gygax says here. In my experience, it was pretty much standard operating procedure amongst the groups with which I had contact. However, this is the first time I can recall its ever being stated outright as the Gospel of Gary. Again, I don't disagree with it, as it's identical to my own practice, but it is nonetheless interesting to see it stated so plainly.