I was looking again at the way Supplement 1 (Greyhawk) describes thief abilities (in preparation for another post.) Specifically, I was looking at this thief ability: "open locks by picking or foiling magical closures". I've made a big deal in the past about the last bit, the "magical closures". Pretty much every version of D&D after Greyhawk, and all the retroclones (so far as I know,) drop the ability to open a magically-locked door or chest.
But now I'm thinking there is more than one way to parse it. I was looking at it as "(open locks by picking) or (foiling magical closures)" -- two related abilities. But what if it's really "open locks by (picking or foiling magical closures)"? What if it is specifically the ability to pick magical locks and devices, and not mundane locks, which are assumed to be automatically openable by the thief?