"(c) Where one or more lighting outlet(s) are installed for interior stairways, there shall be a wall switch at each floor level, and landing level that includes an entryway, to control the lighting outlet(s) where the stairway between floor levels has six risers or more. "
A lot of what I am seeing these days is not actual switches, but PIR switching on stairwells. Where as a given flight of stairs might have a sensor on it, it will trigger on movement at the bottom of the stairs and also trigger a delay timer at the top of that set of stairs, that energises the next PIR (and lights) and turns off the lower lighting. If it saves lights being left on all night,, I'm all for it.
Having said that, in fire situations, it's all lights on.
My wife follows me round the house switching them off, which is nearly the same but with added mutterings about utility bills ! Seriously, you could lose all the cost saving advantages of low-energy lights if the switch timers are of too short a duration. They don't like short runs.
Harold: It will depend on the definition/use of the 'attic'.
Pull down stairs for access to the space I would say only a switch at the entry, walk-up stairs to a space that could be 'occupied' may require a 3-way. Intent and design fall into the discussion at that point.