I think he was smokin' somethin'...
I'd be willing to bet that most AHJ's consider stacking NM Cable (more than one in a staple) to be more of a no-no than running them "parallel". The new "stackers" make stacking legal, since the devices are listed for such use, but I know of no staple that is listed for more than one cable. Personally, I use Plastic Cable Straps, instead of metal staples.
Correct me if I'm wrong, guys... I'm going on "memory" here... (to lazy tonight to go to the truck and get the book again).
Which brings up a question... just when does the "bundling of cables" and derating come into play with stacked NM, and what distance is "far enough" for "paralleled" (NO, not electrically!) cables?
I think sparky tried to get this question going once, it raises it's ugly head again!