I also like the phrase 'junk rig': apart from anything else, it keeps us honest. It's hard to take yourself too seriously when you refer to your boat as a junk. I think Gary's definition: full-length battens to which sheets are attached sums it up well. And yes, we each may have reservations about extreme variations on the theme, but we all pretty much know what we mean by junk rig.
However, I think that the JRA should also be promoting the Hasler/McLeod ethos. I remember talking to Jock McLeod before we fitted a pram hood to Badger. He was quite shocked that we didn't have one, explaining that the ideas that he and Blondie had worked up, concluded in a three-fold concept: junk rig, wind-vane self-steering and the pram hood. They were equally important, ensuring that the boat was easily handled and that the crew could handle the boat from a sheltered position. After fitting a pram hood, I agreed completely with this. It was wonderful to be able to keep watch, to hear and to smell, to be able instantly to alter course or attend to the sails and yet to be sheltered and comfortable.
In promoting junk rig, the JRA is promoting a type of sailing that is both safe and pleasurable.