OK…now I will chime in with my perspective.
While it is a common tendency to “quote” others like Mr. Holt I can promise you he is not always correct(none of us SO-CALLED Experts are 100% of the time). In fact, I have emails from Mr.Holt to prove it. However, he is entitled to his opinion which some do indeed take as gospel. In this case it is his opinion because quite frankly that is how an electrician would wire it and he caters to Electricians.
The NEC does indeed say “wall switch”, that wall switch at each floor level, landing or entryway will indeed have to control the lighting outlets(s) installed on that interior stairway. (paraphrasing of course for brevity) so Mr. Port is technically code correct.
The building code does require a specific amount of illumination to the stairway. If the installer wants to add (2) lighting outlets(s) in the stairway and control each at the separate locations that would be compliant in terms of the NEC. However, it would not be practical and to be honest look quite foolish in my opinion.
So in Mr. Holts statement he is just speaking to the normal installation practice of installing 3-way (or 4-way) switching to accomplish the task at hand. Yet as discussed and highly impractical, the installer could control individual lighting outlet(s) from each location as long as it will seek an effort to meet the illumination requirements of the building codes. While the NEC really does not focus on that it has to work along with it in regards to our combined inspection AHJ world.
So with that said…in terms of HI’s, you are not NEC enforcers and code officials so if it is possible to turn on a luminaire and walk down a set of stairs that would not be fully illuminated unless you turned on another switch for a separate luminaire elsewhere in the stairway, causing the occupant to walk through non-illuminated portions of the stairway then it is a potential safety concern and thats the HI’s focus.
Now for our Code Debate - The language of NEC 210.70(A)(2)© says that you will have lighting outlet(s) in the interior stairway. The last part of the sentence says that wall switch at each location shall control the lighting outlets…so one could argue that if you install the lighting outlet(s) that all of the switches for those lighting outlet(s) have to control those “lighting outlets”…
So cost being what it is…if you installed a single lighting outlet and assuming it provides ample coverage (1 FC) then that lighting outlet would have to be controlled at both ends of the stairway (if six risers or more)…and the only physical way to do it is with a 3-way switch. (dual lamped luminaries not considered…lol…its a dwelling…lol).
Just my thoughts on it…knowing what the code says…then knowing that HI’s should ignore this and report on the safety aspect of the installation only.