> Any use of commas in a list for something other than separating items, regardless of Oxford comma, makes for ambiguous sentences.

I've always felt that the use of parentheses for grouping is under-explored:

    To ((my mother (Ayn Rand)) and God).

Of course, this conflicts with the well ingrained tendency to subconsciously delete parentheticals, but, while pipe-dreaming, one could imagine different marks:

    To {{my mother {Ayn Rand}} and God}.

I'm actually serious about my belief that this sort of thing is logically sensible, but recognise its practical drawbacks ((a) everyone likes the visual appearance of Lisp, right? and (b) everyone speaks Esperanto or Lojban because of its logical primacy, right?).

Not so. There, you unambiguously have a list. If you have a list with a comma in an item, you separate list items with semicolons. So if Ayn Rand was the mother, then it would be "To my mother, Ayn Rand; Jimmy; Bobbie and Sue." The original is difficult because, if "Ayn Rand" is actually subordinated and not a list item, then you don't have a place to put a list separator at all.

Well, an argument in favour of the Oxford comma in that sentence is that Ayn Rand didn't have any children, as anyone who would care for the name would know, so it's clearly a list of three items. :)