Is Order part of a result set?
Possibly the ANSI 92 definition held at

http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt

gives the answer. Section 3.1 Definitions seems to draw a distinction between the idea of a result set and a result sequence. The distinction was not in my awareness when I wrote the question using the former phrase


  v) sequence: An ordered collection of objects that are not necessarily
  distinct.
  
  w) set: An unordered collection of distinct objects. The collection
  may be empty.