What is the role of the slash ("/") in chemical reactions?
The ambiguity seems to come not so much from Chemistry, but from English punctuation. Slashes are often used in place of "and", "or", or the latin "cum" (meaning combined with). It seems that it unfortunately is just context dependent, though I would argue its use as a replacement for "or" is most consistent grammatically and defining this to be the meaning of the slash would eliminate ambiguity in these situations.