They aren't nonsense - a couple weren't right, but they were all based on the very good advice to not just assume that the permanent live goes to COM and to not just assume that the blacks (or blues, as it turns out) are neutrals.
Now we know that 2 browns go to COM it's extraordinarily unlikely that those assumptions would have been wrong, but that doesn't make it nonsense to advise against doing designs based on them.
)
