A vertical stick's shadow at solar noon should be straight north/south, right?
Your understanding is correct, the shadow of a vertical stick on a level plane always points north or south at solar noon, except in the Tropics where sometimes it will not have any shadow due to the Sun being at the zenith, and at the Poles, where solar noon is undefined. The sun can also be below the horizon at solar noon: places inside a polar circle can experience polar night, when the Sun does not rise for at least an entire day. On those days, even at solar noon, the Sun remains below the horizon.

This erroneous passage seems to originate from edits on 13 April 2012. The original text made more sense:


  On the Equator, the sun will be straight overhead and a vertical stick
  will cast no shadow at noon (solar time) on March 21 and September 23,
  the equinox. 23.5 degrees north of the equator on the Tropic of
  Cancer, a vertical stick will cast no shadow on June 21, the summer
  solstice for the northern hemisphere. The rest of the year, the noon
  shadow will point to the North pole. 23.5 degrees south of the equator
  on the Tropic of Capricorn, a vertical stick will cast no shadow on
  December 21, the summer solstice for the southern hemisphere, and the
  rest of the year its noon shadow will point to the South pole. North
  of the Tropic of Cancer, the noon shadow will always point north, and
  conversely, south of the Tropic of Capricorn, the noon shadow will
  always point south.